β-Adrenergic-mediated vasodilation in young men and women: cyclooxygenase restrains nitric oxide synthase

Jacqueline K Limberg; Rebecca E Johansson; Garrett L Peltonen; John W Harrell; J Mikhail Kellawan; Marlowe W Eldridge; Joshua J Sebranek; William G Schrage

doi:10.1152/ajpheart.00886.2015

. 2016 Jan 8;310(6):H756–H764. doi: 10.1152/ajpheart.00886.2015

β-Adrenergic-mediated vasodilation in young men and women: cyclooxygenase restrains nitric oxide synthase

Jacqueline K Limberg ¹, Rebecca E Johansson ¹, Garrett L Peltonen ¹, John W Harrell ¹, J Mikhail Kellawan ¹, Marlowe W Eldridge ^1,², Joshua J Sebranek ³, William G Schrage ^1,^✉

PMCID: PMC4867341 PMID: 26747505

In contrast to present thought, β-adrenergic-mediated vasodilation, and the independent contributions of nitric oxide synthase and cyclooxygenase, are remarkably similar in young men and women. These data are also the first to demonstrate β-adrenoceptor activation of the cyclooxygenase pathway actively suppresses nitric oxide synthase signaling in human forearm microcirculation.

Keywords: isoproterenol, blood flow, prostaglandin, sex differences, skeletal muscle

Abstract

We tested the hypothesis that women exhibit greater vasodilator responses to β-adrenoceptor stimulation compared with men. We further hypothesized women exhibit a greater contribution of nitric oxide synthase and cyclooxygenase to β-adrenergic-mediated vasodilation compared with men. Forearm blood flow (Doppler ultrasound) was measured in young men (n = 29, 26 ± 1 yr) and women (n = 33, 25 ± 1 yr) during intra-arterial infusion of isoproterenol (β-adrenergic agonist). In subset of subjects, isoproterenol responses were examined before and after local inhibition of nitric oxide synthase [N^G-monomethyl-l-arginine (l-NMMA); 6 male/10 female] and/or cyclooxygenase (ketorolac; 5 male/5 female). Vascular conductance (blood flow ÷ mean arterial pressure) was calculated to assess vasodilation. Vascular conductance increased with isoproterenol infusion (P < 0.01), and this effect was not different between men and women (P = 0.41). l-NMMA infusion had no effect on isoproterenol-mediated dilation in men (P > 0.99) or women (P = 0.21). In contrast, ketorolac infusion markedly increased isoproterenol-mediated responses in both men (P < 0.01) and women (P = 0.04) and this rise was lost with subsequent l-NMMA infusion (men, P < 0.01; women, P < 0.05). β-Adrenergic vasodilation is not different between men and women and sex differences in the independent contribution of nitric oxide synthase and cyclooxygenase to β-mediated vasodilation are not present. However, these data are the first to demonstrate β-adrenoceptor activation of cyclooxygenase suppresses nitric oxide synthase signaling in human forearm microcirculation and may have important implications for neurovascular control in both health and disease.

NEW & NOTEWORTHY

In contrast to present thought, β-adrenergic-mediated vasodilation, and the independent contributions of nitric oxide synthase and cyclooxygenase, are remarkably similar in young men and women. These data are also the first to demonstrate β-adrenoceptor activation of the cyclooxygenase pathway actively suppresses nitric oxide synthase signaling in human forearm microcirculation.

young women exhibit lower cardiovascular disease risk compared with men (26). Part of this cardioprotection may be attributed to increased peripheral β-adrenergic-mediated vasodilation. For example, the relationship between sympathetic nervous system activity and total peripheral resistance observed in young men is present in women only during β-adrenoceptor blockade (16). Furthermore, when β-adrenoceptors are blocked, sympathetically-mediated vasoconstriction is increased in women but not in men (16). Consistent with this idea, young women exhibit greater vasodilator responses to intra-arterial albuterol (β₂-adrenoceptor agonist) during the late follicular phase (days 10–14) of the menstrual cycle compared with men (22). Unfortunately, in this case it is difficult to separate the influence of sex per se due to acute increases in sex hormone levels (e.g., estradiol) (22).

Given the importance of β-adrenergic signaling in cardiovascular health and support for the presence of sex differences, it is surprising only one study has directly compared β-adrenergic vasodilation between men and women. Furthermore, the mechanisms mediating potential sex differences are unclear, given inhibition of nitric oxide synthase (NOS) did not alter the observed differences between men and women (22). Along these lines, although nitric oxide (NO) is thought to play a role in vasodilator responses to β-adrenergic stimulation, the effect of NOS inhibition is variable and has been shown to only partially reduce the vasodilator effect of β-adrenoceptor stimulation (2, 4, 9, 12, 14, 22). These results suggest β-adrenergic vasodilation may be achieved by NO-independent mechanisms. Consistent with this, data from animal models suggest cyclooxygenase (COX) may influence β-adrenergic vasodilation (25, 34, 40). However, the contribution of COX to β-adrenergic vasodilation in the forearm microcirculation, and the potential for sex differences, remain untested in humans.

Therefore, we sought to examine potential sex differences in β-adrenergic vasodilation and the relative contributions of NOS and COX. We hypothesized during the early follicular phase of the menstrual cycle, young women would exhibit greater vasodilator responses to β-adrenoceptor activation compared with men. Furthermore, we hypothesized women would exhibit a greater relative contribution of NOS and COX to β-adrenergic vasodilation compared with men. In this way, we were able to examine fundamental sex differences, independent of any role of acute increases in sex hormone levels.

MATERIALS AND METHODS

Sixty-two young (18–40 yr) men (n = 29) and women (n = 33) participated in the current study (Table 1). Subjects were healthy, nonsmokers, and nonobese and were not taking any cardiovascular medications. Women were not pregnant and were studied during the early follicular phase (days 1–5) of the menstrual cycle. Subjects underwent a minimum 10-h fast and refrained from exercise, nonsteroidal anti-inflammatory drugs, alcohol, and caffeine for 24-h before the study visit. Written informed consent was obtained from all subjects. All procedures were approved by the Institutional Review Board at the University of Wisconsin-Madison and conformed to the standards set by the Declaration of Helsinki.

Table 1.

Subject demographics

	ISO Alone (Protocols 1, 2, and 3)		ISO + l-NMMA (Protocol 2)		ISO + Ketorolac (Protocol 3)
	Men	Women	Men	Women	Men	Women
n	29	33	6	10	5	5
Age, yr	26 ± 1	25 ± 1	24 ± 2	22 ± 1	24 ± 3	27 ± 2
Height, cm	177 ± 2	166 ± 1^*	183 ± 4	167 ± 2^*	175 ± 3	163 ± 2^*
Weight, kg	71 ± 2	61 ± 1^*	78 ± 4	60 ± 2^*	67 ± 2	56 ± 5^*
BMI, kg/m²	23 ± 2	22 ± 1	23 ± 1	22 ± 1	22 ± 1	20 ± 1
Body fat, %	20 ± 1	33 ± 1^*	20 ± 3	32 ± 3^*	19 ± 2	32 ± 2^*
Forearm lean mass, g	962 ± 28	586 ± 14^*	1,048 ± 65	577 ± 27^*	924 ± 55	550 ± 11^*

Open in a new tab

Values are means ± SE.

ISO, isoproterenol; l-NMMA, N^G-monomethyl-l-arginine; BMI, body mass index.

P < 0.05 vs. men.

Forearm blood flow (artery diameter, blood velocity) was measured using Doppler ultrasound (Vivid 7; General Electric, Milwaukee, WI) with the subject supine using methods published previously (21, 24, 33). With the use of technology developed by Herr et al. (18), the Doppler audio information from the ultrasound was converted into a real-time digital flow velocity signal using fast Fourier transform (18). This method of signal processing has been validated by both in vitro and in vivo methods (18). Beat-to-beat brachial artery blood velocity and blood pressure (arterial catheter; Transpac IV Monitoring Kit; ICU Medical; San Clemente, CA) were obtained throughout each trial.

All drugs were infused via a brachial artery catheter placed in the nondominant arm in the antecubital fossa. Isoproterenol (isoproterenol hydrochloride injection; Marathon Pharmaceuticals) was infused at four separate doses (1, 3, 6, and 12 ng·100 g⁻¹·min⁻¹), similar to those published previously (10, 11, 17). N^G-monomethyl-l-arginine (l-NMMA; acetate; Clinalfa BaChem) was infused at a rate of 10 mg/min over 5 min, followed by a 1 mg/min maintenance dose (5, 7, 21). Ketorolac (ketorolac tromethamine; Wockhardt) was infused at a rate of 1.2 mg/min for 5 min, followed by a 0.1 mg/min maintenance dose (7, 21).

Three study protocols were conducted (Fig. 1). Protocol 1 (18 male/18 female) consisted of one trial: 1) isoproterenol. Protocol 2 (6 male/10 female) consisted of three trials: 1) isoproterenol, 2) isoproterenol + l-NMMA, and 3) isoproterenol + l-NMMA and ketorolac. Protocol 3 (5 male/5 female) consisted of three trials: 1) isoproterenol, 2) isoproterenol + ketorolac, and 3) isoproterenol + ketorolac and l-NMMA. Two minutes of resting data were acquired at the start of each trial. Each dose of isoproterenol was infused for 3 min for a total infusion length of 12 min. After a minimum of 10 min of quiet rest, a loading dose of l-NMMA or ketorolac was administered over 5 min, followed by a continuous maintenance dose. In protocols 2 and 3, isoproterenol infusions were repeated. After a minimum of 10 min, a loading dose of the second inhibitor (ketorolac or l-NMMA) was administered over 5 min, followed by a continuous maintenance dose. Isoproterenol infusions were repeated a final time. There were no observable differences in the responses to “double-blockade” (l-NMMA and ketorolac) when l-NMMA was given first vs. the trials where ketorolac was administered first (P = 0.328; unpublished observations).

Data were sampled in real time with signal-processing software (PowerLab; ADInstruments, Colorado Springs, CO), digitized, and analyzed offline. Postprocessing using PowerLab Chart5 yielded mean blood velocity and blood pressure. Steady-state hemodynamics were measured during the last 30 s of saline and each dose of isoproterenol. Diameter measurements were taken immediately before increasing dosage, were assessed offline from B-mode images, and were taken as the median of five measurements in late diastole. Blood flow was calculated as the product of mean blood velocity (cm/s) and vessel cross-sectional area (radius in cm²) and was reported in ml·min⁻¹·100 g⁻¹ [(blood velocity)(cross-sectional area)(60 s/min) ÷ forearm lean mass]. To account for potential changes in blood pressure and assess vasodilation, vascular conductance (ml·min⁻¹·100 g⁻¹·100 mmHg) was calculated [blood flow ÷ mean arterial blood pressure].

The primary analysis was to examine sex differences in vascular conductance responses to isoproterenol (protocol 1). The secondary analysis was to examine the effect of NOS (protocol 2) and/or COX (protocol 3) inhibition on isoproterenol-mediated increases in vascular conductance. To account for any group differences in resting vascular conductance, the main dependent variable was a change in vascular conductance (VC) from baseline levels (ΔVC; VC_condition − VC_rest). Area under the curve (AUC) above baseline was also calculated over isoproterenol doses and expressed as a percentage of the control response [%VC AUC; (AUC _condition) ÷ (AUC _control) × 100]. Trial 1 data (isoproterenol dose response) were pooled across protocols for analysis (Fig. 1).

Statistical analysis was completed using SigmaStat 12.0 software (Systat Software, San Jose, CA). Subject characteristics were compared using a Student's unpaired t-test, and hemodynamic variables were analyzed using a two-way repeated ANOVA approach to determine the significance of the fixed effect of group, dose, and/or blockade on parameters of interest (protocol 1: group-by-dose and interaction; protocols 2 and 3: dose-by-blockade and interaction). Area under the curve analysis was conducted using an unpaired t-test (protocol 1: group) or two-way repeated measures ANOVA (protocols 2 and 3: group-by-blockade). Bonferroni post hoc comparisons were performed when significant effects were observed. All data are presented as mean ± SE, and significance was determined a priori at P ≤ 0.05.

Sample sizes for protocols 1 and 2 were determined a priori by power test equations with α = 0.05 and power = 0.80, using group differences from previously published data (4, 6, 17, 22). Protocol 1 required a minimum of 13 subjects per group, which was exceeded (men, n = 29; women, n = 33). Protocol 2 required a minimum of six subjects per group, which was also exceeded (men, n = 6; women, n = 10). In protocol 3, we first studied five individuals in each group (n = 10 total) based on previous work by our group (38) to obtain a preliminary estimate of the variability of the response between men and women and the potential magnitude of an effect. A post hoc power analysis for protocol 3 indicated ∼100 subjects would be necessary to detect sex differences with α = 0.05 and power = 0.80. This analysis suggests it is unlikely any lack of sex difference is a result of the study being underpowered.

RESULTS

Heart rate and blood pressure were not different between men and women (Table 2; P value range 0.465–0.785). Furthermore, infusion of isoproterenol had no effect on heart rate (Tables 2–4) or blood pressure in either group (Tables 2–4), except at the highest dose of isoproterenol (heart rate: Table 3; blood pressure: Tables 3 and 4). Brachial artery diameter was significantly greater in men compared with women (Table 2; main effect of group, P < 0.001) and increased with isoproterenol infusion (Tables 2–4; main effect of ISO, P < 0.05); however, this effect was not different between the sexes (Tables 2–4; interaction effect, P > 0.05).

Table 2.

Effect of sex on the hemodynamic response to acute isoproterenol infusion (protocols 1, 2, and 3)

	Baseline	1 ng·100 g⁻¹·min⁻¹	3 ng·100 g⁻¹·min⁻¹	6 ng·100 g⁻¹·min⁻¹	12 ng·100 g⁻¹·min⁻¹	Main Effect of Group	Main Effect of ISO	Interaction Effect^#
Brachial artery diameter, cm
Men	0.41 ± 0.01	0.42 ± 0.01	0.42 ± 0.01^a	0.42 ± 0.01^a	0.43 ± 0.01^a^,^b^,^c^,^d	<0.001	<0.001	—
Women^*	0.33 ± 0.01	0.34 ± 0.01	0.34 ± 0.01^a	0.34 ± 0.01^a	0.35 ± 0.01^a^,^b^,^c^,^d
Heart rate, beats/min
Men	62 ± 2	63 ± 2	63 ± 2	63 ± 2	64 ± 2	0.465	0.707	—
Women	63 ± 2	64 ± 1	63 ± 1	63 ± 1	65 ± 2
Mean arterial blood pressure, mmHg
Men	84 ± 2	84 ± 1	84 ± 1	84 ± 1	85 ± 1	0.785	0.507	—
Women	85 ± 1	85 ± 1	84 ± 1	84 ± 1	85 ± 2
Lean forearm blood flow, ml·min⁻¹·100 g⁻¹
Men	6 ± 1	9 ± 1^a	11 ± 1^a^,^b	15 ± 1^a^,^b^,^c	19 ± 1^a^,^b^,^c^,^d	0.621	<0.001	—
Women	5 ± 0	8 ± 1^a	11 ± 1^a^,^b	15 ± 1^a^,^b^,^c	18 ± 1^a^,^b^,^c^,^d
Lean forearm vascular conductance, ml·min⁻¹·100 g⁻¹·100 mmHg
Men	8 ± 1	11 ± 1^a	14 ± 1^a^,^b	18 ± 1^a^,^c^,^c	22 ± 2^a^,^b^,^c^,^d	0.406	<0.001	—
Women	6 ± 0	9 ± 1^a	13 ± 1^a^,^b	18 ± 1^a^,^c^,^c	22 ± 1^a^,^b^,^c^,^d

Open in a new tab

Values are means ± SE. Men: n = 29; women: n = 33.

P < 0.05 vs. baseline;

P < 0.05 vs. 1 ng·100 g⁻¹·min⁻¹;

P < 0.05 vs. 3 ng·100 g⁻¹·min⁻¹;

P < 0.05 vs. 6 ng·100 g⁻¹·min⁻¹.

P < 0.05 vs. men.

From the initial model that included the group-by-ISO interaction effect, no significant interaction was detected (P > 0.05). Italicized values denote statistical significance.

Table 4.

Effect of sex and ketorolac on the hemodynamic response to acute isoproterenol infusion (protocol 3)

	Baseline	1 ng·100 g⁻¹·min⁻¹	3 ng·100 g⁻¹·min⁻¹	6 ng·100 g⁻¹·min⁻¹	12 ng·100 g⁻¹·min⁻¹	Main Effect of ISO	Main Effect of Ketorolac	Interaction Effect^#
Brachial artery diameter, cm
Men ISO alone	0.42 ± 0.02	0.42 ± 0.03	0.42 ± 0.02	0.44 ± 0.02^a	0.44 ± 0.02^a^,^b	0.001	0.523	—
Men ketorolac	0.44 ± 0.02	0.43 ± 0.02	0.45 ± 0.02	0.45 ± 0.02^a	0.46 ± 0.02^a^,^b
Men DB	0.42 ± 0.02	0.44 ± 0.02	0.44 ± 0.02	0.44 ± 0.02^a	0.45 ± 0.02^a^,^b
Women ISO alone	0.32 ± 0.02	0.33 ± 0.03	0.32 ± 0.01	0.32 ± 0.02	0.32 ± 0.02	0.050	0.192	—
Women ketorolac	0.32 ± 0.01	0.33 ± 0.02	0.33 ± 0.02	0.35 ± 0.02	0.35 ± 0.02
Women DB	0.32 ± 0.01	0.32 ± 0.01	0.32 ± 0.01	0.32 ± 0.01	0.33 ± 0.01
Heart rate, beats/min
Men ISO alone	61 ± 6	63 ± 7	64 ± 6	62 ± 6	65 ± 7	0.058	0.204	—
Men ketorolac	59 ± 5	59 ± 5	58 ± 5	60 ± 5	54 ± 3
Men DB	63 ± 8	57 ± 4	63 ± 5	59 ± 6	61 ± 6
Women ISO alone	67 ± 5	70 ± 4	68 ± 5	71 ± 3	71 ± 5	0.495	0.337	—
Women ketorolac	71 ± 2	67 ± 5	72 ± 2	70 ± 5	72 ± 4
Women DB	67 ± 3	65 ± 3	66 ± 4	68 ± 3	67 ± 3
Mean arterial blood pressure, mmHg
Men ISO alone	78 ± 7	79 ± 3	80 ± 3	81 ± 3	78 ± 3	0.561	0.011	—
Men ketorolac	82 ± 3	80 ± 3	79 ± 3	78 ± 3	79 ± 4
Men DB	86 ± 3	84 ± 2	83 ± 2	82 ± 3	83 ± 3
Women ISO alone	79 ± 3	78 ± 2	78 ± 3	76 ± 2	76 ± 2^a	0.006	0.211	0.024
Women ketorolac	79 ± 3	78 ± 2	76 ± 3	76 ± 2	76 ± 2^a^,^b^,^c
Women DB	82 ± 4	81 ± 4	82 ± 4	83 ± 5	83 ± 5
Lean forearm blood flow, ml·min⁻¹·100 g⁻¹
Men ISO alone	8 ± 1	9 ± 1	11 ± 1	16 ± 2^a	20 ± 3^a^,^b^,^c	<0.001	<0.001	0.023
Men ketorolac	7 ± 1	10 ± 1	17 ± 2^†^§^a^,^b	20 ± 2^§^a^,^b	25 ± 3^†^§^a^,^b^,^c
Men DB	5 ± 2	7 ± 2	9 ± 1	11 ± 2^‡	15 ± 3^‡^a^,^b
Women ISO alone	5 ± 2	7 ± 3	10 ± 3	14 ± 6	16 ± 5^a^,^b	<0.001	0.038	<0.001
Women ketorolac	8 ± 3	11 ± 4	19 ± 6^§^a	26 ± 9^†^§^a^,^b	32 ± 9^†^§^a^,^b^,^c
Women DB	6 ± 2	6 ± 1	9 ± 3	13 ± 2	18 ± 4^a^,^b^,^c
Lean forearm vascular conductance, ml·min⁻¹·100 g⁻¹·100 mmHg
Men ISO alone	10 ± 1	12 ± 2	14 ± 1	19 ± 2^a	26 ± 3^a^,^b^,^c	<0.001	<0.001	0.026
Men ketorolac	9 ± 1	12 ± 2	21 ± 2^†^§^a^,^b	25 ± 2^§^a^,^b	32 ± 5^†^§^a^,^b^,^c
Men DB	6 ± 2	8 ± 2	11 ± 2	14 ± 2	18 ± 3^‡^a^,^b
Women ISO alone	7 ± 2	9 ± 3	13 ± 4	19 ± 7^a	22 ± 7^a^,^b	<0.001	0.036	<0.001
Women ketorolac	9 ± 3	14 ± 5	24 ± 7^§^a	33 ± 11^†^§^a^,^b	40 ± 10^†^§^a^,^b^,^c
Women DB	7 ± 2	7 ± 1	11 ± 2	15 ± 2	21 ± 4^a^,^b

Open in a new tab

Values are means ± SE. Men: n = 5; women: n = 5.

P < 0.05 vs. baseline;

P < 0.05 vs. 1 ng·100 g⁻¹·min⁻¹;

P < 0.05 vs. 3 ng·100 g⁻¹·min⁻¹;

P < 0.05 vs. 6 ng·100 g⁻¹·min⁻¹.

^†

P < 0.05 ISO vs. ketorolac;

^‡

P < 0.05 ISO vs. DB;

^§

P < 0.05 ketorolac vs. DB.

From the initial model that included the ISO-by-ketorolac interaction effect, no significant interaction was detected in the case of missing variables (P > 0.05). Italicized values denote statistical significance.

Table 3.

Effect of sex and l-NMMA on the hemodynamic response to acute isoproterenol infusion (protocol 2)

	Baseline	1 ng·100 g⁻¹·min⁻¹	3 ng·100 g⁻¹·min⁻¹	6 ng·100 g⁻¹·min⁻¹	12 ng·100 g⁻¹·min⁻¹	Main Effect of ISO	Main Effect of l-NMMA	Interaction Effect^#
Brachial artery diameter, cm
Men ISO Alone	0.39 ± 0.02	0.40 ± 0.02	0.40 ± 0.02	0.40 ± 0.02^a	0.42 ± 0.02^a^,^b^,^c	<0.001	0.016	—
Men l-NMMA	0.40 ± 0.02	0.41 ± 0.02	0.41 ± 0.02	0.41 ± 0.02^a	0.42 ± 0.02^a^,^b^,^c
Men DB^‡	0.41 ± 0.02	0.42 ± 0.02	0.41 ± 0.02	0.43 ± 0.02^a	0.43 ± 0.02^a^,^b^,^c
Women ISO Alone	0.33 ± 0.01	0.33 ± 0.01	0.33 ± 0.01^a^,^b	0.34 ± 0.01^a^,^b	0.34 ± 0.01^a^,^b	<0.001	0.058	—
Women l-NMMA	0.33 ± 0.01	0.33 ± 0.01	0.33 ± 0.01^a^,^b	0.34 ± 0.01^a^,^b	0.33 ± 0.01^a^,^b
Women DB	0.33 ± 0.01	0.33 ± 0.01	0.35 ± 0.01^a^,^b	0.35 ± 0.01^a^,^b	0.35 ± 0.01^a^,^b
Heart rate, beats/min
Men ISO alone	61 ± 4	61 ± 4	60 ± 4	60 ± 4	64 ± 3	0.061	0.094	—
Men l-NMMA	59 ± 3	58 ± 4	59 ± 3	62 ± 3	64 ± 3
Men DB	57 ± 3	60 ± 5	58 ± 3	59 ± 3	61 ± 3
Women ISO Alone	62 ± 3	64 ± 3	64 ± 3	64 ± 2	66 ± 3^a^,^b^,^c	0.018	0.002	—
Women l-NMMA^†	61 ± 3	59 ± 3	56 ± 3	60 ± 3	62 ± 2^a^,^b^,^c
Women DB^‡	57 ± 2	59 ± 3	61 ± 2	63 ± 4	65 ± 2^a^,^b^,^c
Mean arterial blood pressure, mmHg
Men ISO alone	88 ± 2	87 ± 3	87 ± 2	87 ± 3	87 ± 3	0.927	0.015	—
Men l-NMMA	91 ± 2	90 ± 3	88 ± 3	90 ± 3	90 ± 3
Men DB^‡	91 ± 3	92 ± 3	93 ± 3	92 ± 3	92 ± 4
Women ISO alone	85 ± 2	86 ± 2	86 ± 2	87 ± 3	89 ± 3^a	0.039	0.003	—
Women l-NMMA^†	91 ± 2	89 ± 2	91 ± 2	91 ± 2	92 ± 2^a
Women DB^‡	91 ± 2	91 ± 2	92 ± 1	92 ± 2	94 ± 2^a
Lean forearm blood flow, ml·min⁻¹·100 g⁻¹
Men ISO alone	6 ± 1	8 ± 1	14 ± 2^a	16 ± 2^a^,^b	21 ± 4^a^,^b^,^c	<0.001	0.971	—
Men l-NMMA	6 ± 2	9 ± 2	13 ± 3^a	17 ± 3^a^,^b	21 ± 4^a^,^b^,^c
Men DB	5 ± 1	9 ± 1	11 ± 2^a	18 ± 5^a^,^b	22 ± 4^a^,^b^,^c
Women ISO alone	5 ± 2	7 ± 1	12 ± 1^a^,^b	15 ± 2^a^,^b^,^c	18 ± 2^a^,^b^,^c^,^d	<0.001	0.378	—
Women l-NMMA	5 ± 1	6 ± 1	10 ± 2^a^,^b	13 ± 2^a^,^b^,^c	15 ± 2^a^,^b^,^c^,^d
Women DB	4 ± 1	6 ± 1	11 ± 1^a^,^b	15 ± 2^a^,^b^,^c	20 ± 2^a^,^b^,^c^,^d
Lean forearm vascular conductance, ml·min⁻¹·100 g⁻¹·100 mmHg
Men ISO alone	6 ± 1	9 ± 1	15 ± 2^a	19 ± 3^a^,^b	24 ± 5^a^,^b^,^c	<0.001	0.902	—
Men l-NMMA	6 ± 1	10 ± 1	14 ± 3^a	19 ± 3^a^,^b	23 ± 4^a^,^b^,^c
Men DB	6 ± 1	10 ± 1	12 ± 2^a	19 ± 4^a^,^b	23 ± 4^a^,^b^,^c
Women ISO alone	6 ± 1	8 ± 0	13 ± 1^a^,^b	18 ± 2^a^,^b^,^c	21 ± 2^a^,^b^,^c^,^d	<0.001	0.214	—
Women l-NMMA	6 ± 2	7 ± 2	11 ± 2^a^,^b	15 ± 2^a^,^b^,^c	17 ± 2^a^,^b^,^c^,^d
Women DB	5 ± 1	6 ± 1	12 ± 1^a^,^b	16 ± 2^a^,^b^,^c	21 ± 2^a^,^b^,^c^,^d

Open in a new tab

Values are means ± SE. Men: n = 6; women: n = 10. DB, double blockade (l-NMMA + ketorolac).

P < 0.05 vs. baseline;

P < 0.05 vs. 1 ng·100 g⁻¹·min⁻¹;

P < 0.05 vs. 3 ng·100 g⁻¹·min⁻¹;

P < 0.05 vs. 6 ng·100 g⁻¹·min⁻¹.

^†

P < 0.05 ISO vs. l-NMMA;

^‡

P < 0.05 ISO vs. DB.

From the initial model that included the ISO-by-l-NMMA interaction effect, no significant interaction was detected (P > 0.05). Italicized values denote statistical significance.

Isoproterenol resulted in a dose-dependent increase in vascular conductance that did not differ between men and women (Table 2). Conclusions were maintained when assessed as a change in vascular conductance (Fig. 2A: effect of isoproterenol, P < 0.001; sex, P = 0.388). Furthermore, area under the curve responses were not different between men and women (Fig. 2B: P = 0.386).

Fig. 2. — Hemodynamic response to isoproterenol. A and B: vascular conductance increases with isoproterenol, and the effect is not different between men and women. ^aP < 0.05 vs. 1 ng·100 g⁻¹·min⁻¹; ^bP < 0.05 vs. 3 ng·100 g⁻¹·min⁻¹; ^cP < 0.05 vs. 6 ng·100 g⁻¹·min⁻¹.

In a second group of subjects (men n = 6, women n = 10), isoproterenol resulted in a dose-dependent increase in vascular conductance, with responses seen primarily at higher doses (3–12 ng·100 g⁻¹·min⁻¹; Table 3). l-NMMA alone and/or combined with ketorolac had no detectable effect on isoproterenol-mediated vasodilation in men or women (Table 3). Conclusions were maintained when assessed as a change in vascular conductance from baseline in men (Fig. 3A; effect of isoproterenol, P < 0.001; condition, P = 0.999) and women (Fig. 3B: effect of isoproterenol, P < 0.001; condition, P = 0.381). Furthermore, l-NMMA alone and/or combined with ketorolac had no detectable effect on absolute (Fig. 3C: effect of sex, P = 0.404; condition, P = 0.472) or relative (Fig. 3D: effect of sex, P = 0.963; condition, P = 0.587) area under the curve analyses.

Fig. 3. — Effect N^G-monomethyl-l-arginine (l-NMMA) on the hemodynamic response to isoproterenol. A–D: vascular conductance increases with isoproterenol in women and men. There is no effect of l-NMMA alone and/or combined with ketorolac in women or men. AUC, area under the curve. ^aP < 0.05 vs. 1 ng·100 g⁻¹·min⁻¹; ^bP < 0.05 vs. 3 ng·100 g⁻¹·min⁻¹; ^cP < 0.05 vs. 6 ng·100 g⁻¹·min⁻¹.

In a third group of subjects (men n = 5, women n = 5), isoproterenol resulted in a dose-dependent increase in vascular conductance, with responses seen primarily at higher doses (6–12 ng·100 g⁻¹·min⁻¹; Table 4). In men, ketorolac resulted in a significant increase in isoproterenol-mediated vasodilation (Table 4). Specifically, there was an increase in isoproterenol-mediated vasodilation at 3, 6, and 12 ng·100 g⁻¹·min⁻¹ (P = 0.017, P = 0.071, and P = 0.041), which was attenuated with subsequent l-NMMA infusion (P < 0.001 for all). Combined ketorolac and l-NMMA resulted in isoproterenol-mediated vasodilation that was not different from saline levels at 1, 3, and 6 ng·100 g⁻¹·min⁻¹ (P = 0.265, P = 0.456, and P = 0.084). During the 12 ng·100 g⁻¹·min⁻¹ infusion, combined/double blockade resulted in isoproterenol-mediated vasodilation that was lower than that observed with saline alone (P = 0.011). Conclusions were maintained when assessed as a change in vascular conductance (Fig. 4A: effect of isoproterenol, P < 0.001; condition, P = 0.031).

Fig. 4. — Effect of ketorolac on the hemodynamic response to isoproterenol. A–D: vascular conductance increased with isoproterenol in women and men. Ketorolac increased isoproterenol-mediated vasodilation in women and men. The effect of ketorolac was not different between women and men. ^aP < 0.05 vs. 1 ng·100 g⁻¹·min⁻¹; ^bP < 0.05 vs. ng·100 g⁻¹·min⁻¹. †P < 0.05 isoproterenol vs. ketorolac; §P < 0.05 ketorolac vs. ketorolac + l-NMMA.

In women, ketorolac resulted in a significant increase in isoproterenol-mediated vasodilation (Table 4). Specifically, ketorolac increased isoproterenol-mediated vasodilation at 3, 6, and 12 ng·100 g⁻¹·min⁻¹ (P = 0.080, P = 0.021, and P = 0.003), which was attenuated with subsequent l-NMMA infusion (P = 0.033, P = 0.005, and P = 0.003). Combined ketorolac and l-NMMA resulted in isoproterenol-mediated vasodilation that was not different from saline levels (range P = 0.743 to P = 0.879). Conclusions were maintained when assessed as a change in vascular conductance (Fig. 4B: effect of isoproterenol, P < 0.001; condition, P = 0.026; interaction, P = 0.006).

Area under the curve responses were augmented with ketorolac (effect of condition, P = 0.001; saline vs. ketorolac: P = 0.007) and returned to saline levels with coinfusion of l-NMMA (ketorolac vs. double blockade: P = 0.001; saline vs. double blockade: P = 0.678; Fig. 4C). This effect was not different between men and women (effect of sex, P = 0.567). Conclusions were maintained when area under the curve was examined relative to baseline levels (Fig. 4D: effect of condition, P < 0.001; sex, P = 0.329).

DISCUSSION

Our mechanistic approach uncovered four novel findings: 1) β-adrenergic-mediated vasodilation is remarkably similar between young men and women (Fig. 2); 2) NOS inhibition alone has minimal effect on β-adrenergic vasodilation in men or women (Fig. 3); 3) inhibition of COX increases β-adrenergic vasodilation in both sexes (Fig. 4); and 4) combined NOS and COX inhibition returns isoproterenol-mediated vasodilation to control levels (Fig. 4), indicating COX activity limits β-adrenergic vasodilation by suppressing NOS. These data provide novel mechanistic insight to our overall understanding of the interactions among sex, β-adrenergic vasodilation, and contributing mechanisms.

Although recent research suggests cardioprotection seen in young women may be attributed to an increase in peripheral β-adrenergic-mediated vasodilation, only one study has directly compared β-adrenergic receptor responsiveness between young men and women (22). Kneale et al. showed during the late follicular phase (days 10–14) of the menstrual cycle, young women exhibit greater vasodilator responses to β₂-adrenoceptor stimulation when compared with men (22). Contrary to findings from Kneale et al., the present results show β-adrenergic vasodilation is not different between men and women (Fig. 1). We propose three possible explanations for the discrepancies between findings.

First, Kneale et. al. (22) gave absolute doses of β-adrenoceptor agonist to men and women, despite men having significantly larger forearm size and baseline blood flow. In this way, women received relatively higher doses of drug per unit of forearm mass compared with men, which may explain, at least in part, the greater vasodilation observed in women (22). To address this limitation, we infused isoproterenol relative to lean forearm mass and compared vasodilator responses to the same relative β-adrenoceptor stimulus between groups. This methodology is widely accepted (10, 11, 17).

Second, Kneale et. al. (22) assessed forearm blood flow using venous occlusion plethysmography whereas the present study used Doppler ultrasound. Both are accepted as reliable measures of limb blood flow; however, Crecelius et. al. (8) found differences between methodologies when similar research questions were addressed. It is possible Doppler ultrasound measures a greater contribution of the cutaneous circulation compared with plethysmography. Importantly, young women exhibit greater β-adrenergic-mediated cutaneous vasodilation compared with men (15). Therefore, any contribution of the cutaneous circulation would lead us to overestimate (rather than underestimate) β-adrenoceptor responsiveness in women.

Third, Kneale et. al. (22) studied women during days 10–14 of the menstrual cycle, when estrogen levels are increasing. This approach cannot differentiate between acute changes in sex hormones (e.g., estradiol) and fundamental sex differences. In contrast, we studied women during the early follicular phase of the menstrual cycle; therefore, any effects of acute elevations in endogenous female sex hormones on β-adrenoceptor sensitivity are minimized. With this information in mind, we propose the following: 1) differences in β-adrenoceptor sensitivity between men and women observed by Kneale et. al. (22) were the result of women receiving a relatively higher dose of drug per unit of forearm mass compared with men and thus it is unlikely sex differences in β-adrenergic vasodilation are present, or 2) there is no overt sex difference in β-adrenoceptor sensitivity during the low hormone phase (Fig. 2), but rather sex differences in β-adrenergic vasodilation are only observed when endogenous female sex hormone levels (e.g., estradiol) are high (22). This idea is supported by data from Harvey et al. (17), who have shown vasodilator responses to isoproterenol tend to be lower in postmenopausal (low hormone) vs. premenopausal (high hormone) women.

NO is thought to play a role in the vasodilator responses to β-adrenoceptor stimulation; however, previous studies have shown the effect of NOS inhibition is variable (0–60%) and only partially reduces the vasodilator effect of β-adrenoceptor stimulation (2, 4, 9, 12, 14, 22). Consistent with this, we found the contribution of NOS was relatively small in both groups (1–12%) and no sex differences were observed (Fig. 3). These data led us to consider β-adrenergic vasodilation may be achieved by NOS-independent mechanisms. One potential NOS-independent signal is COX-derived prostacyclin, a potent vasodilator in the peripheral vasculature. β-Adrenoceptor activation has been shown previously to mediate prostacyclin synthesis (25, 34, 40). Furthermore, β₂-adrenergic-mediated coronary vasodilation is impaired with indomethacin (a COX inhibitor)(3). Therefore, we hypothesized ketorolac would attenuate isoproterenol-mediated vasodilation. Surprisingly, ketorolac infusion increased isoproterenol-mediated vasodilation in both sexes (Fig. 4). These novel findings are the first in human forearm microvasculature to indicate COX products limit β-adrenergic vasodilation in both men and women.

Ketorolac nonspecifically inhibits COX production of both “vasodilating” (e.g., prostacyclin) and “vasoconstricting” (e.g., thromboxanes) prostaglandins. Although research is limited in humans, inhibition of COX can increase β-adrenergic vasodilation in canine (36), porcine, bovine (35), and sheep coronary arteries (28) and in isolated perfused rat and cat hearts (42, 43). These data, combined with those from the present study, suggest prostanoids attenuate β-adrenergic vasodilation. Consistent with this concept, exogenous prostaglandin I₂ can inhibit β-adrenoceptor responsiveness (37). Perhaps, by inhibiting COX, the production of prostaglandin I₂ is interrupted, thus lifting its inhibitory effect on β-adrenergic vasodilation. It is also possible COX products other than prostaglandin I₂ (e.g., prostaglandin E₂) are involved (36). Furthermore, the rise in isoproterenol-mediated dilation with ketorolac infusion may be due to an indirect effect of COX products on bioavailable NO and/or NOS. In support of this: 1) NOS isoforms and COX interact (29), 2) thromboxane increases oxidative stress which inhibits bioavailable NO (44), and 3) thromboxane can directly inhibit NOS (27, 46).

Interestingly, our data support such NOS/COX interactions. Whereas ketorolac essentially doubled isoproterenol-mediated vasodilation, this rise in conductance was abolished with l-NMMA (Fig. 4). These data indicate β-adrenoceptor activation of the COX pathway suppresses NO signaling in human forearm microvasculature. Thus the presence of COX byproducts likely attenuates any effect of NO on β-adrenergic vasodilation. Our results are consistent with studies conducted in the cutaneous circulation in humans, which demonstrate COX products inhibit NOS, and COX inhibition unmasks the contribution of NOS to vasodilation (27). The exact location of these interactions is unknown. In this way, it is important to recognize the net vascular responses to a β-adrenergic agonist are complex and can be derived from signaling on both the vascular smooth muscle and endothelium-mediated responses. Furthermore, vascular tonus is modulated by endothelium-derived relaxing factors (31), including vasodilator prostaglandins, NO, and endothelium-dependent hyperpolarization factors, as well as vasoconstrictor substances, in which both NOS and COX are substantially involved. While we provide evidence that an interplay between NOS and COX contributes to the vasodilatory response to β-adrenergic receptor stimulation in the forearm microcirculation, future studies will be necessary to examine the contribution of such additional factors.

Based on the present findings, an imbalance between NOS and COX could play an important role in differences in β-adrenergic receptor-mediated vasodilation in health and disease. For example, perhaps COX levels are reduced during the luteal phase of the menstrual cycle, thus allowing more NOS-mediated vasodilation with β-adrenergic receptor stimulation in women at that time. Furthermore, conditions of increased COX signaling (e.g., aging, hypertension, diabetes) may exhibit attenuated β-adrenergic receptor-mediated vasodilation due to COX restraint of NOS and thus may play an important role in neural control of blood flow and/or blood pressure regulation in such conditions. Additionally, varying levels of COX restraint could explain the wide range of studies showing an incredibly variable (0–60%) contribution of NOS to β-adrenergic receptor-mediated vasodilation (2, 4, 9, 12, 14, 22). Taken together, the present findings support a new role for COX in modulating β-adrenergic receptor-mediated vascular control and provide rationale for future mechanistic studies in blood pressure and blood flow regulation in disease states and/or environmental stressors.

The current study included a robust sample of healthy men and women studied across three protocols under tight experimental control, including standard relative dosing and use of inhibitors to strategically explore vascular control mechanisms. However, there are some limitations to consider. First, isoproterenol infusion may increase local norepinephrine spillover via stimulation of presynaptic β₂-adrenoceptors(41). It is unknown if these presynaptic receptors differ by sex, but given men exhibit greater α-adrenergic receptor responsiveness compared with women (19, 22), any relative increase in norepinephrine release would lead to greater constriction in men, leading us to underestimate (rather than overestimate) the extent of β-adrenergic vasodilation in men. These results would still be contrary to our main hypothesis. Second, we did not measure sex hormone levels. However, we are confident female sex hormones (e.g., estradiol and progesterone) were low given identical recruiting and scheduling methods to prior studies from our laboratory (23, 32). Third, the present study utilized a nonselective β-adrenoceptor agonist [compared with the use of albuterol, a selective β₂-adrenoceptor agonist, by Kneale et al. (22)]. However, this is a minor limitation given the following: 1) isoproterenol is an established pharmacological tool to examine β-adrenergic vasodilation in the human microcirculation (10, 11, 17); 2) metoprolol does not impair isoproterenol-mediated vasodilation whereas isoproterenol responses are abolished with propranolol [indicating any vasodilation is principally β₂-adrenoceptor mediated (13)]; and 3) β₁-adrenoceptor subtypes are more predominant in large conduit arteries whereas β₂-adrenoceptor subtypes are more common in the microvasculature (1, 13, 30, 39, 45). Given that the present study was designed to examine microvascular function, we propose the primary effect of isoproterenol is likely at the level of the β₂-adrenoceptors. Fourth, slight increases in brachial artery diameter (0.01–0.02 cm) were also observed. Given that all drugs were infused downstream of the brachial artery measurement site and directly into the local forearm microcirculation, it is unlikely the observed changes were the result of a direct effect of the infused drugs on the conduit artery. Rather, we propose dilation of the brachial artery was an indirect effect of vasodilation within the forearm microcirculation, increasing shear stress in the brachial artery to the extent that slight flow-mediated vasodilation was achieved. Lastly, although all drugs were infused locally and were dosed relative to forearm size to limit systemic effects, in some instances we observed modest changes in blood pressure (1–4 mmHg) and heart rate (2–4 beats/min). These changes, while modest, highlight the possibility that under specific study conditions, the drugs exerted systemic effects, possibly resulting in a direct effect of isoproterenol on the heart and/or changes in the level of baroreflex activation. Importantly, changes in measures of blood pressure and heart rate were modest, were observed only at the highest dose of isoproterenol, and did not have a large impact on only one sex (men or women). For these reasons, it is unlikely differential systemic effects significantly affected our conclusions.

In conclusion, β-adrenergic receptor responsiveness in the forearm microvasculature is remarkably similar in young healthy men and women. Furthermore, the individual contributions of NOS and COX to β-adrenergic vasodilation are not different between sexes. However, these data are the first to demonstrate β-adrenoceptor activation of the COX pathway actively suppresses NO signaling in human forearm microcirculation. Taken together, these findings provide novel mechanistic insight to our overall understanding of the interactions among sex, β-adrenergic vasodilation, and contributing mechanisms. Furthermore, our results have important implications for understanding blood flow and blood pressure regulation in both health and disease.

GRANTS

This work was supported by National Heart, Lung, and Blood Institute Grant HL-105820 (to W. G. Schrage) and F32-HL-120570 (to J. K. Limberg).

DISCLOSURES

No conflicts of interest, financial or otherwise, are declared by the author(s).

AUTHOR CONTRIBUTIONS

Author contributions: J.K.L., R.J., G.L.P., J.W.H., and J.M.K. analyzed data; J.K.L., R.J., G.L.P., and W.G.S. interpreted results of experiments; J.K.L. prepared figures; J.K.L. drafted manuscript; J.K.L., R.J., G.L.P., J.W.H., J.M.K., M.W.E., J.J.S., and W.G.S. edited and revised manuscript; J.K.L., R.J., G.L.P., J.W.H., J.M.K., M.W.E., J.J.S., and W.G.S. approved final version of manuscript; R.J., G.L.P., J.W.H., J.M.K., M.W.E., J.J.S., and W.G.S. performed experiments; M.W.E., J.J.S., and W.G.S. conception and design of research.

ACKNOWLEDGMENTS

Our deepest appreciation and thanks to the research participants. We also thank Meghan Crain, Josh Trierweiler, Cameron Rousseau, Brady Ernst, and Mariah Marino.

REFERENCES

1.Amenta F, Coppola L, Gallo P, Ferrante F, Forlani A, Monopoli A, Napoleone P. Autoradiographic localization of beta-adrenergic receptors in human large coronary arteries. Circ Res 68: 1591–1599, 1991. [DOI] [PubMed] [Google Scholar]
2.Bea ML, Ghaleh B, Giudicelli JF, Berdeaux A. Lack of importance of NO in beta-adrenoceptor-mediated relaxation of large epicardial canine coronary arteries. Br J Pharmacol 111: 981–982, 1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
3.Brousseau D, Desjardins JF, Jasmin G, Dumont L. Altered coronary and cardiac adrenergic response in the failing hamster heart: role of cyclooxygenase derivatives. Can J Physiol Pharmacol 80: 218–225, 2002. [DOI] [PubMed] [Google Scholar]
4.Cardillo C, Kilcoyne CM, Quyyumi AA, Cannon RO 3rd, Panza JA. Decreased vasodilator response to isoproterenol during nitric oxide inhibition in humans. Hypertension 30: 918–921, 1997. [DOI] [PubMed] [Google Scholar]
5.Casey DP, Ranadive SM, Joyner MJ. Aging is associated with altered vasodilator kinetics in dynamically contracting muscle: role of nitric oxide. J Appl Physiol 119: 232–241, 2015. [DOI] [PMC free article] [PubMed] [Google Scholar]
6.Casey DP, Walker BG, Curry TB, Joyner MJ. Ageing reduces the compensatory vasodilatation during hypoxic exercise: the role of nitric oxide. J Physiol 589: 1477–1488, 2011. [DOI] [PMC free article] [PubMed] [Google Scholar]
7.Crecelius AR, Kirby BS, Hearon CM Jr, Luckasen GJ, Larson DG, and Dinenno FA. Contracting human skeletal muscle maintains the ability to blunt alpha1 -adrenergic vasoconstriction during KIR channel and Na(+) /K(+) -ATPase inhibition. J Physiol 593: 2735–2751, 2015. [DOI] [PMC free article] [PubMed] [Google Scholar]
8.Crecelius AR, Kirby BS, Richards JC, Garcia LJ, Voyles WF, Larson DG, Luckasen GJ, Dinenno FA. Mechanisms of ATP-mediated vasodilation in humans: modest role for nitric oxide and vasodilating prostaglandins. Am J Physiol Heart Circ Physiol 301: H1302–H1310, 2011. [DOI] [PMC free article] [PubMed] [Google Scholar]
9.Dawes M, Chowienczyk PJ, Ritter JM. Effects of inhibition of the l-arginine/nitric oxide pathway on vasodilation caused by beta-adrenergic agonists in human forearm. Circulation 95: 2293–2297, 1997. [DOI] [PubMed] [Google Scholar]
10.Eisenach JH, Schroeder DR, Pavey ES, Penheiter AR, Knutson JN, Turner ST, Joyner MJ. Interactions between beta-2 adrenoceptor gene variation, cardiovascular control and dietary sodium in healthy young adults. J Physiol 592: 5221–5233, 2014. [DOI] [PMC free article] [PubMed] [Google Scholar]
11.Eisenach JH, Schroeder DR, Pike TL, Johnson CP, Schrage WG, Snyder EM, Johnson BD, Garovic VD, Turner ST, Joyner MJ. Dietary sodium restriction and beta2-adrenergic receptor polymorphism modulate cardiovascular function in humans. J Physiol 574: 955–965, 2006. [DOI] [PMC free article] [PubMed] [Google Scholar]
12.Ferro A, Queen LR, Priest RM, Xu B, Ritter JM, Poston L, Ward JP. Activation of nitric oxide synthase by beta 2-adrenoceptors in human umbilical vein endothelium in vitro. Br J Pharmacol 126: 1872–1880, 1999. [DOI] [PMC free article] [PubMed] [Google Scholar]
13.Gao F, de Beer VJ, Hoekstra M, Xiao C, Duncker DJ, Merkus D. Both beta1- and beta2-adrenoceptors contribute to feedforward coronary resistance vessel dilation during exercise. Am J Physiol Heart Circ Physiol 298: H921–H929, 2010. [DOI] [PubMed] [Google Scholar]
14.Gray DW, Marshall I. Novel signal transduction pathway mediating endothelium-dependent beta-adrenoceptor vasorelaxation in rat thoracic aorta. Br J Pharmacol 107: 684–690, 1992. [DOI] [PMC free article] [PubMed] [Google Scholar]
15.Greaney JL, Stanhewicz AE, Kenney WL, Alexander LM. Lack of limb or sex differences in the cutaneous vascular responses to exogenous norepinephrine. J Appl Physiol 117: 1417–1423, 2014. [DOI] [PMC free article] [PubMed] [Google Scholar]
16.Hart EC, Charkoudian N, Wallin BG, Curry TB, Eisenach J, Joyner MJ. Sex and ageing differences in resting arterial pressure regulation: the role of the beta-adrenergic receptors. J Physiol 589: 5285–5297, 2011. [DOI] [PMC free article] [PubMed] [Google Scholar]
17.Harvey RE, Barnes JN, Charkoudian N, Curry TB, Eisenach JH, Hart EC, Joyner MJ. Forearm vasodilator responses to a beta-adrenergic receptor agonist in premenopausal and postmenopausal women. Physiol Rep 2: e12032, 2014. [DOI] [PMC free article] [PubMed] [Google Scholar]
18.Herr MD, Hogeman CS, Koch DW, Krishnan A, Momen A, Leuenberger UA. A real-time device for converting Doppler ultrasound audio signals into fluid flow velocity. Am J Physiol Heart Circ Physiol 298: H1626–H1632, 2010. [DOI] [PMC free article] [PubMed] [Google Scholar]
19.Hogarth AJ, Mackintosh AF, Mary DA. Gender-related differences in the sympathetic vasoconstrictor drive of normal subjects. Clin Sci (Lond) 112: 353–361, 2007. [DOI] [PubMed] [Google Scholar]
20.Joyner MJ, Dietz NM, Shepherd JT. From Belfast to Mayo and beyond: the use and future of plethysmography to study blood flow in human limbs. J Appl Physiol 91: 2431–2441, 2001. [DOI] [PubMed] [Google Scholar]
21.Kellawan JM, Johansson RE, Harrell JW, Sebranek JJ, Walker BJ, Eldridge MW, Schrage WG. Exercise vasodilation is greater in women: contributions of nitric oxide synthase and cyclooxygenase. Eur J Appl Physiol 115: 1735–1746, 2015. [DOI] [PMC free article] [PubMed] [Google Scholar]
22.Kneale BJ, Chowienczyk PJ, Brett SE, Coltart DJ, Ritter JM. Gender differences in sensitivity to adrenergic agonists of forearm resistance vasculature. J Am Coll Cardiol 36: 1233–1238, 2000. [DOI] [PubMed] [Google Scholar]
23.Limberg JK, Eldridge MW, Proctor LT, Sebranek JJ, Schrage WG. Alpha-adrenergic control of blood flow during exercise: effect of sex and menstrual phase. J Appl Physiol 109: 1360–1368, 2010. [DOI] [PMC free article] [PubMed] [Google Scholar]
24.Limberg JK, Harrell JW, Johansson RE, Eldridge MW, Proctor LT, Sebranek JJ, Schrage WG. Microvascular function in younger adults with obesity and metabolic syndrome: role of oxidative stress. Am J Physiol Heart Circ Physiol 305: H1230–H1237, 2013. [DOI] [PMC free article] [PubMed] [Google Scholar]
25.Malik KU. Interaction of arachidonic acid metabolites and adrenergic nervous system. Am J Med Sci 295: 280–286, 1988. [DOI] [PubMed] [Google Scholar]
26.Martins D, Nelson K, Pan D, Tareen N, Norris K. The effect of gender on age-related blood pressure changes and the prevalence of isolated systolic hypertension among older adults: data from NHANES III. J Gend Specif Med 4: 10–13, 20, 2001. [PubMed] [Google Scholar]
27.Medow MS, Taneja I, Stewart JM. Cyclooxygenase and nitric oxide synthase dependence of cutaneous reactive hyperemia in humans. Am J Physiol Heart Circ Physiol 293: H425–H432, 2007. [DOI] [PMC free article] [PubMed] [Google Scholar]
28.Miller RC, Cornish EJ, Goldie RG. Potentiating effect of indomethacin on relaxations of sheep isolated coronary artery caused by sympathetic nerve stimulation or exogenous noradrenaline. Pharmacol Res Commun 16: 31–39, 1984. [DOI] [PubMed] [Google Scholar]
29.Mollace V, Muscoli C, Masini E, Cuzzocrea S, Salvemini D. Modulation of prostaglandin biosynthesis by nitric oxide and nitric oxide donors. Pharmacol Rev 57: 217–252, 2005. [DOI] [PubMed] [Google Scholar]
30.Murphree SS, Saffitz JE. Delineation of the distribution of beta-adrenergic receptor subtypes in canine myocardium. Circ Res 63: 117–125, 1988. [DOI] [PubMed] [Google Scholar]
31.Ozkor MA, Murrow JR, Rahman AM, Kavtaradze N, Lin J, Manatunga A, Quyyumi AA. Endothelium-derived hyperpolarizing factor determines resting and stimulated forearm vasodilator tone in health and in disease. Circulation 123: 2244–2253, 2011. [DOI] [PMC free article] [PubMed] [Google Scholar]
32.Peltonen GL, Harrell JW, Rousseau CL, Ernst BS, Marino ML, Crain MK, Schrage WG. Cerebrovascular regulation in men and women: stimulus-specific role of cyclooxygenase. Physiol Rep 3: e12451, 2015. [DOI] [PMC free article] [PubMed] [Google Scholar]
33.Ranadive SM, Joyner MJ, Walker BG, Taylor JL, Casey DP. Effect of vitamin C on hyperoxia-induced vasoconstriction in exercising skeletal muscle. J Appl Physiol 117: 1207–1211, 2014. [DOI] [PMC free article] [PubMed] [Google Scholar]
34.Ruan Y, Kan H, Malik KU. Beta adrenergic receptor stimulated prostacyclin synthesis in rabbit coronary endothelial cells is mediated by selective activation of phospholipase D: inhibition by adenosine 3′5′-cyclic monophosphate. J Pharmacol Exp Ther 281: 1038–1046, 1997. [PubMed] [Google Scholar]
35.Rubanyi G, Paul RJ. O₂-sensitivity of beta adrenergic responsiveness in isolated bovine and porcine coronary arteries. J Pharmacol Exp Ther 230: 692–698, 1984. [PubMed] [Google Scholar]
36.Rubanyi G, Vanhoutte PM. Inhibitors of prostaglandin synthesis augment beta-adrenergic responsiveness in canine coronary arteries. Circ Res 56: 117–125, 1985. [DOI] [PubMed] [Google Scholar]
37.Rubanyi GM, Paul RJ. Modulation of beta adrenergic responsiveness by arachidonic acid metabolites in isolated bovine coronary arteries. J Pharmacol Exp Ther 234: 555–560, 1985. [PubMed] [Google Scholar]
38.Schrage WG, Dietz NM, Eisenach JH, Joyner MJ. Agonist-dependent variablity of contributions of nitric oxide and prostaglandins in human skeletal muscle. J Appl Physiol 98: 1251–1257, 2005. [DOI] [PubMed] [Google Scholar]
39.Schwartz J, Velly J. The beta-adrenoceptor of pig coronary arteries: determination of beta 1 and beta 2 subtypes by radioligand binding. Br J Pharmacol 79: 409–414, 1983. [DOI] [PMC free article] [PubMed] [Google Scholar]
40.Shaffer JE, Malik KU. Enhancement of prostaglandin output during activation of beta-1 adrenoceptors in the isolated rabbit heart. J Pharmacol Exp Ther 223: 729–735, 1982. [PubMed] [Google Scholar]
41.Stein M, Deegan R, He H, Wood AJ. Beta-adrenergic receptor-mediated release of norepinephrine in the human forearm. Clin Pharmacol Ther 54: 58–64, 1993. [DOI] [PubMed] [Google Scholar]
42.Sunahara FA, Talesnik J. Prostaglandin inhibition of metabolically induced coronary vasodilation. J Pharmacol Exp Ther 188: 135–147, 1974. [PubMed] [Google Scholar]
43.Talesnik J, Sunahara FA. Enhancement of metabolic coronary dilatation by aspirin-like substances by suppression of prostaglandin feedback control? Nature 244: 351–353, 1973. [DOI] [PubMed] [Google Scholar]
44.Tang M, Cyrus T, Yao Y, Vocun L, Pratico D. Involvement of thromboxane receptor in the proatherogenic effect of isoprostane F2alpha-III: evidence from apolipoprotein E- and LDL receptor-deficient mice. Circulation 112: 2867–2874, 2005. [DOI] [PubMed] [Google Scholar]
45.Toda N, Okamura T. Beta adrenoceptor subtype in isolated human, monkey and dog epicardial coronary arteries. J Pharmacol Exp Ther 253: 518–524, 1990. [PubMed] [Google Scholar]
46.Yamada T, Fujino T, Yuhki K, Hara A, Karibe H, Takahata O, Okada Y, Xiao CY, Takayama K, Kuriyama S, Taniguchi T, Shiokoshi T, Ohsaki Y, Kikuchi K, Narumiya S, Ushikubi F. Thromboxane A2 regulates vascular tone via its inhibitory effect on the expression of inducible nitric oxide synthase. Circulation 108: 2381–2386, 2003. [DOI] [PubMed] [Google Scholar]

[B1] 1.Amenta F, Coppola L, Gallo P, Ferrante F, Forlani A, Monopoli A, Napoleone P. Autoradiographic localization of beta-adrenergic receptors in human large coronary arteries. Circ Res 68: 1591–1599, 1991. [DOI] [PubMed] [Google Scholar]

[B2] 2.Bea ML, Ghaleh B, Giudicelli JF, Berdeaux A. Lack of importance of NO in beta-adrenoceptor-mediated relaxation of large epicardial canine coronary arteries. Br J Pharmacol 111: 981–982, 1994. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B3] 3.Brousseau D, Desjardins JF, Jasmin G, Dumont L. Altered coronary and cardiac adrenergic response in the failing hamster heart: role of cyclooxygenase derivatives. Can J Physiol Pharmacol 80: 218–225, 2002. [DOI] [PubMed] [Google Scholar]

[B4] 4.Cardillo C, Kilcoyne CM, Quyyumi AA, Cannon RO 3rd, Panza JA. Decreased vasodilator response to isoproterenol during nitric oxide inhibition in humans. Hypertension 30: 918–921, 1997. [DOI] [PubMed] [Google Scholar]

[B5] 5.Casey DP, Ranadive SM, Joyner MJ. Aging is associated with altered vasodilator kinetics in dynamically contracting muscle: role of nitric oxide. J Appl Physiol 119: 232–241, 2015. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B6] 6.Casey DP, Walker BG, Curry TB, Joyner MJ. Ageing reduces the compensatory vasodilatation during hypoxic exercise: the role of nitric oxide. J Physiol 589: 1477–1488, 2011. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B7] 7.Crecelius AR, Kirby BS, Hearon CM Jr, Luckasen GJ, Larson DG, and Dinenno FA. Contracting human skeletal muscle maintains the ability to blunt alpha1 -adrenergic vasoconstriction during KIR channel and Na(+) /K(+) -ATPase inhibition. J Physiol 593: 2735–2751, 2015. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B8] 8.Crecelius AR, Kirby BS, Richards JC, Garcia LJ, Voyles WF, Larson DG, Luckasen GJ, Dinenno FA. Mechanisms of ATP-mediated vasodilation in humans: modest role for nitric oxide and vasodilating prostaglandins. Am J Physiol Heart Circ Physiol 301: H1302–H1310, 2011. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B9] 9.Dawes M, Chowienczyk PJ, Ritter JM. Effects of inhibition of the l-arginine/nitric oxide pathway on vasodilation caused by beta-adrenergic agonists in human forearm. Circulation 95: 2293–2297, 1997. [DOI] [PubMed] [Google Scholar]

[B10] 10.Eisenach JH, Schroeder DR, Pavey ES, Penheiter AR, Knutson JN, Turner ST, Joyner MJ. Interactions between beta-2 adrenoceptor gene variation, cardiovascular control and dietary sodium in healthy young adults. J Physiol 592: 5221–5233, 2014. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B11] 11.Eisenach JH, Schroeder DR, Pike TL, Johnson CP, Schrage WG, Snyder EM, Johnson BD, Garovic VD, Turner ST, Joyner MJ. Dietary sodium restriction and beta2-adrenergic receptor polymorphism modulate cardiovascular function in humans. J Physiol 574: 955–965, 2006. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B12] 12.Ferro A, Queen LR, Priest RM, Xu B, Ritter JM, Poston L, Ward JP. Activation of nitric oxide synthase by beta 2-adrenoceptors in human umbilical vein endothelium in vitro. Br J Pharmacol 126: 1872–1880, 1999. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B13] 13.Gao F, de Beer VJ, Hoekstra M, Xiao C, Duncker DJ, Merkus D. Both beta1- and beta2-adrenoceptors contribute to feedforward coronary resistance vessel dilation during exercise. Am J Physiol Heart Circ Physiol 298: H921–H929, 2010. [DOI] [PubMed] [Google Scholar]

[B14] 14.Gray DW, Marshall I. Novel signal transduction pathway mediating endothelium-dependent beta-adrenoceptor vasorelaxation in rat thoracic aorta. Br J Pharmacol 107: 684–690, 1992. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B15] 15.Greaney JL, Stanhewicz AE, Kenney WL, Alexander LM. Lack of limb or sex differences in the cutaneous vascular responses to exogenous norepinephrine. J Appl Physiol 117: 1417–1423, 2014. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B16] 16.Hart EC, Charkoudian N, Wallin BG, Curry TB, Eisenach J, Joyner MJ. Sex and ageing differences in resting arterial pressure regulation: the role of the beta-adrenergic receptors. J Physiol 589: 5285–5297, 2011. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B17] 17.Harvey RE, Barnes JN, Charkoudian N, Curry TB, Eisenach JH, Hart EC, Joyner MJ. Forearm vasodilator responses to a beta-adrenergic receptor agonist in premenopausal and postmenopausal women. Physiol Rep 2: e12032, 2014. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B18] 18.Herr MD, Hogeman CS, Koch DW, Krishnan A, Momen A, Leuenberger UA. A real-time device for converting Doppler ultrasound audio signals into fluid flow velocity. Am J Physiol Heart Circ Physiol 298: H1626–H1632, 2010. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B19] 19.Hogarth AJ, Mackintosh AF, Mary DA. Gender-related differences in the sympathetic vasoconstrictor drive of normal subjects. Clin Sci (Lond) 112: 353–361, 2007. [DOI] [PubMed] [Google Scholar]

[B20] 20.Joyner MJ, Dietz NM, Shepherd JT. From Belfast to Mayo and beyond: the use and future of plethysmography to study blood flow in human limbs. J Appl Physiol 91: 2431–2441, 2001. [DOI] [PubMed] [Google Scholar]

[B21] 21.Kellawan JM, Johansson RE, Harrell JW, Sebranek JJ, Walker BJ, Eldridge MW, Schrage WG. Exercise vasodilation is greater in women: contributions of nitric oxide synthase and cyclooxygenase. Eur J Appl Physiol 115: 1735–1746, 2015. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B22] 22.Kneale BJ, Chowienczyk PJ, Brett SE, Coltart DJ, Ritter JM. Gender differences in sensitivity to adrenergic agonists of forearm resistance vasculature. J Am Coll Cardiol 36: 1233–1238, 2000. [DOI] [PubMed] [Google Scholar]

[B23] 23.Limberg JK, Eldridge MW, Proctor LT, Sebranek JJ, Schrage WG. Alpha-adrenergic control of blood flow during exercise: effect of sex and menstrual phase. J Appl Physiol 109: 1360–1368, 2010. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B24] 24.Limberg JK, Harrell JW, Johansson RE, Eldridge MW, Proctor LT, Sebranek JJ, Schrage WG. Microvascular function in younger adults with obesity and metabolic syndrome: role of oxidative stress. Am J Physiol Heart Circ Physiol 305: H1230–H1237, 2013. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B25] 25.Malik KU. Interaction of arachidonic acid metabolites and adrenergic nervous system. Am J Med Sci 295: 280–286, 1988. [DOI] [PubMed] [Google Scholar]

[B26] 26.Martins D, Nelson K, Pan D, Tareen N, Norris K. The effect of gender on age-related blood pressure changes and the prevalence of isolated systolic hypertension among older adults: data from NHANES III. J Gend Specif Med 4: 10–13, 20, 2001. [PubMed] [Google Scholar]

[B27] 27.Medow MS, Taneja I, Stewart JM. Cyclooxygenase and nitric oxide synthase dependence of cutaneous reactive hyperemia in humans. Am J Physiol Heart Circ Physiol 293: H425–H432, 2007. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B28] 28.Miller RC, Cornish EJ, Goldie RG. Potentiating effect of indomethacin on relaxations of sheep isolated coronary artery caused by sympathetic nerve stimulation or exogenous noradrenaline. Pharmacol Res Commun 16: 31–39, 1984. [DOI] [PubMed] [Google Scholar]

[B29] 29.Mollace V, Muscoli C, Masini E, Cuzzocrea S, Salvemini D. Modulation of prostaglandin biosynthesis by nitric oxide and nitric oxide donors. Pharmacol Rev 57: 217–252, 2005. [DOI] [PubMed] [Google Scholar]

[B30] 30.Murphree SS, Saffitz JE. Delineation of the distribution of beta-adrenergic receptor subtypes in canine myocardium. Circ Res 63: 117–125, 1988. [DOI] [PubMed] [Google Scholar]

[B31] 31.Ozkor MA, Murrow JR, Rahman AM, Kavtaradze N, Lin J, Manatunga A, Quyyumi AA. Endothelium-derived hyperpolarizing factor determines resting and stimulated forearm vasodilator tone in health and in disease. Circulation 123: 2244–2253, 2011. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B32] 32.Peltonen GL, Harrell JW, Rousseau CL, Ernst BS, Marino ML, Crain MK, Schrage WG. Cerebrovascular regulation in men and women: stimulus-specific role of cyclooxygenase. Physiol Rep 3: e12451, 2015. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B33] 33.Ranadive SM, Joyner MJ, Walker BG, Taylor JL, Casey DP. Effect of vitamin C on hyperoxia-induced vasoconstriction in exercising skeletal muscle. J Appl Physiol 117: 1207–1211, 2014. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B34] 34.Ruan Y, Kan H, Malik KU. Beta adrenergic receptor stimulated prostacyclin synthesis in rabbit coronary endothelial cells is mediated by selective activation of phospholipase D: inhibition by adenosine 3′5′-cyclic monophosphate. J Pharmacol Exp Ther 281: 1038–1046, 1997. [PubMed] [Google Scholar]

[B35] 35.Rubanyi G, Paul RJ. O₂-sensitivity of beta adrenergic responsiveness in isolated bovine and porcine coronary arteries. J Pharmacol Exp Ther 230: 692–698, 1984. [PubMed] [Google Scholar]

[B36] 36.Rubanyi G, Vanhoutte PM. Inhibitors of prostaglandin synthesis augment beta-adrenergic responsiveness in canine coronary arteries. Circ Res 56: 117–125, 1985. [DOI] [PubMed] [Google Scholar]

[B37] 37.Rubanyi GM, Paul RJ. Modulation of beta adrenergic responsiveness by arachidonic acid metabolites in isolated bovine coronary arteries. J Pharmacol Exp Ther 234: 555–560, 1985. [PubMed] [Google Scholar]

[B38] 38.Schrage WG, Dietz NM, Eisenach JH, Joyner MJ. Agonist-dependent variablity of contributions of nitric oxide and prostaglandins in human skeletal muscle. J Appl Physiol 98: 1251–1257, 2005. [DOI] [PubMed] [Google Scholar]

[B39] 39.Schwartz J, Velly J. The beta-adrenoceptor of pig coronary arteries: determination of beta 1 and beta 2 subtypes by radioligand binding. Br J Pharmacol 79: 409–414, 1983. [DOI] [PMC free article] [PubMed] [Google Scholar]

[B40] 40.Shaffer JE, Malik KU. Enhancement of prostaglandin output during activation of beta-1 adrenoceptors in the isolated rabbit heart. J Pharmacol Exp Ther 223: 729–735, 1982. [PubMed] [Google Scholar]

[B41] 41.Stein M, Deegan R, He H, Wood AJ. Beta-adrenergic receptor-mediated release of norepinephrine in the human forearm. Clin Pharmacol Ther 54: 58–64, 1993. [DOI] [PubMed] [Google Scholar]

[B42] 42.Sunahara FA, Talesnik J. Prostaglandin inhibition of metabolically induced coronary vasodilation. J Pharmacol Exp Ther 188: 135–147, 1974. [PubMed] [Google Scholar]

[B43] 43.Talesnik J, Sunahara FA. Enhancement of metabolic coronary dilatation by aspirin-like substances by suppression of prostaglandin feedback control? Nature 244: 351–353, 1973. [DOI] [PubMed] [Google Scholar]

[B44] 44.Tang M, Cyrus T, Yao Y, Vocun L, Pratico D. Involvement of thromboxane receptor in the proatherogenic effect of isoprostane F2alpha-III: evidence from apolipoprotein E- and LDL receptor-deficient mice. Circulation 112: 2867–2874, 2005. [DOI] [PubMed] [Google Scholar]

[B45] 45.Toda N, Okamura T. Beta adrenoceptor subtype in isolated human, monkey and dog epicardial coronary arteries. J Pharmacol Exp Ther 253: 518–524, 1990. [PubMed] [Google Scholar]

[B46] 46.Yamada T, Fujino T, Yuhki K, Hara A, Karibe H, Takahata O, Okada Y, Xiao CY, Takayama K, Kuriyama S, Taniguchi T, Shiokoshi T, Ohsaki Y, Kikuchi K, Narumiya S, Ushikubi F. Thromboxane A2 regulates vascular tone via its inhibitory effect on the expression of inducible nitric oxide synthase. Circulation 108: 2381–2386, 2003. [DOI] [PubMed] [Google Scholar]

PERMALINK

β-Adrenergic-mediated vasodilation in young men and women: cyclooxygenase restrains nitric oxide synthase

Jacqueline K Limberg

Rebecca E Johansson

Garrett L Peltonen

John W Harrell

J Mikhail Kellawan

Marlowe W Eldridge

Joshua J Sebranek

William G Schrage

Abstract

NEW & NOTEWORTHY