Department of Kinesiology and Applied Physiology, University of Delaware, Newark, Delaware, USA.
Am J Physiol Heart Circ Physiol. 2010 Nov;299(5):H1318-27. doi: 10.1152/ajpheart.00556.2010. Epub 2010 Aug 27.
Recent animal studies have reported that exercise pressor reflex (EPR)-mediated increases in blood pressure are exaggerated in hypertensive (HTN) rodents. Whether these findings can be extended to human hypertension remains unclear. Mean arterial pressure (MAP), muscle sympathetic nerve activity (MSNA), and venous metabolites were measured in normotensive (NTN; n = 23; 60 ± 1 yr) and HTN (n = 15; 63 ± 1 yr) subjects at baseline, and during static handgrip at 30 and 40% maximal voluntary contraction (MVC) followed by a period of postexercise ischemia (PEI) to isolate the metabolic component of the EPR. Changes in MAP from baseline were augmented in HTN subjects during both 30 and 40% MVC handgrip (P < 0.05 for both), and these group differences were maintained during PEI (30% PEI trial: Δ15 ± 2 NTN vs. Δ19 ± 2 HTN mmHg; 40% PEI trial: Δ16 ± 1 NTN vs. Δ23 ± 2 HTN mmHg; P < 0.05 for both). Similarly, in HTN subjects, MSNA burst frequency was greater during 30 and 40% MVC handgrip (P < 0.05 for both), and these differences were maintained during PEI [30% PEI trial: 35 ± 2 (NTN) vs. 44 ± 2 (HTN) bursts/min; 40% PEI trial: 36 ± 2 (NTN) vs. 48 ± 2 (HTN) bursts/min; P < 0.05 for both]. No group differences in metabolites were observed. MAP and MSNA responses to a cold pressor test were not different between groups, suggesting no group differences in generalized sympathetic responsiveness. In summary, compared with NTN subjects, HTN adults exhibit exaggerated sympathetic and pressor responses to handgrip exercise that are maintained during PEI, indicating that activation of the metabolic component of the EPR is augmented in older HTN humans.
最近的动物研究报告称，高血压（HTN）啮齿动物的运动升压反射（EPR）介导的血压升高被夸大了。这些发现是否可以扩展到人类高血压尚不清楚。在基线时，测量了正常血压（NTN；n=23；60±1 岁）和高血压（HTN；n=15；63±1 岁）受试者的平均动脉压（MAP）、肌肉交感神经活动（MSNA）和静脉代谢物，然后在 30%和 40%最大自主收缩（MVC）的静态握力下进行，接着进行运动后缺血（PEI）以分离 EPR 的代谢成分。在 30%和 40% MVC 握力期间，HTN 受试者的 MAP 从基线的变化均增加（两者均 P<0.05），并且这些组间差异在 PEI 期间保持不变（30%PEI 试验：Δ15±2 NTN 与 Δ19±2 HTN mmHg；40%PEI 试验：Δ16±1 NTN 与 Δ23±2 HTN mmHg；两者均 P<0.05）。同样，在 HTN 受试者中，MSNA 爆发频率在 30%和 40% MVC 握力期间更高（两者均 P<0.05），并且这些差异在 PEI 期间保持不变[30%PEI 试验：35±2（NTN）与 44±2（HTN）爆发/分钟；40%PEI 试验：36±2（NTN）与 48±2（HTN）爆发/分钟；两者均 P<0.05]。代谢物无组间差异。冷加压试验时 MAP 和 MSNA 反应在两组之间无差异，提示两组之间普遍的交感神经反应无差异。总之，与 NTN 受试者相比，HTN 成年人在手握运动时表现出交感神经和升压反应的过度增强，这种反应在 PEI 期间得以维持，表明 EPR 的代谢成分在老年 HTN 人群中被增强。
