Table 2.

Peak responses by drug infusion during both thermal conditions

	Preinjection	Nitroprusside	Phenylephrine
	Normothermia
Mean arterial blood pressure, mmHg	110±3	95±4*	116±4†
Heart rate, beats/min	67±4	90±5*	61±3*†
MSNA, bursts/min	33±3	76±7*	24±4*†
MSNA, units/min	610±80	1,391±112*	433±57*†
	Heat stress
Mean arterial blood pressure, mmHg	105±3	92±3*	114±4†
Heart rate, beats/min	91±5‡	113±4*‡	87±5‡
MSNA, bursts/min	54±5‡	88±11*	46±7‡
MSNA, units/min	1,122±160‡	1,629±263*	983±172‡

Data for the preinjection period are mean values of ∼10 s during postexercise muscle ischemia (PEMI) and just before the infusion of sodium nitroprusside. Data for sodium nitroprusside are mean values of ∼10 s during the lowest blood pressure induced by this drug during PEMI. Data for phenylephrine HCl are mean values of ∼10 s during the highest blood pressure induced by phenylephrine HCl during PEMI. It should be noted that the data for the preinjection baseline period were obtained from a very short period, which only provides a reference for the operating range in the baroreflex and does not constitute stable responses during PEMI.

^*P < 0.05 compared with preinjection.

^†P <0.05 compared with sodium nitroprusside.

^‡P <0.05 compared with normothermia.