Table 3.

Effect of low-dose dopamine infusion on the hypoxic and cardiovascular response to hypoxia

	Saline	1 μg·kg−1·min−1	2 μg·kg−1·min−1	3 μg·kg−1·min−1	4 μg·kg−1·min−1	Effect of Dose
Hypoxic ventilatory response [(liters/min)/%]
All	0.35 ± 0.04	0.26 ± 0.03*	0.23 ± 0.03*†	0.28 ± 0.03*†‡	0.24 ± 0.03*†§	<0.001
High HVR	0.53 ± 0.05	0.35 ± 0.05*	0.31 ± 0.05*	0.35 ± 0.04*	0.30 ± 0.05*	<0.001
Low HVR	0.22 ± 0.01	0.19 ± 0.03	0.16 ± 0.03	0.23 ± 0.04	0.20 ± 0.03	0.319
Hypoxic heart rate response [(beat/min)/%]
All	1.08 ± 0.11	0.95 ± 0.09	0.89 ± 0.07	0.84 ± 0.08	1.01 ± 0.09	0.238
High HVR	1.35 ± 0.22	0.98 ± 0.16*	0.85 ± 0.08*	0.79 ± 0.10*	1.11 ± 0.16*	0.023
Low HVR	0.88 ± 0.08	0.93 ± 0.11	0.92 ± 0.11	0.88 ± 0.12	0.94 ± 0.10	0.948
Hypoxic blood pressure response (mmHg/%)
All	0.52 ± 0.08	0.36 ± 0.04*	0.40 ± 0.06†	0.49 ± 0.06†	0.47 ± 0.05†	0.047
High HVR	0.93 ± 0.19	0.56 ± 0.10*	0.63 ± 0.15	0.62 ± 0.14	0.62 ± 0.10	0.034
Low HVR	0.36 ± 0.05	0.33 ± 0.06	0.37 ± 0.06	0.51 ± 0.08	0.47 ± 0.08	0.050

Data reported as means ± SE, n = 30 unless otherwise noted (high n = 13, low n = 17).

^*P < 0.05 vs. saline,

^†P < 0.05 vs. 1 μg·kg⁻¹·min⁻¹,

^‡P < 0.05 vs. 2 μg·kg⁻¹·min⁻¹,

^§P < 0.05 vs. 3 μg·kg⁻¹·min⁻¹.

Numbers in bold represent statistical significance.