MODULATION OF SYMPATHETIC-NERVE ACTIVITY DURING POSTHANDGRIP MUSCLE ISCHEMIA IN HUMANS

被引:29
作者
RAY, CA
SECHER, NH
MARK, AL
机构
[1] UNIV IOWA, DEPT INTERNAL MED, CTR CARDIOVASC, IOWA CITY, IA 52242 USA
[2] UNIV IOWA, DEPT VET AFFAIRS, IOWA CITY, IA 52242 USA
[3] UNIV COPENHAGEN, RIGSHOSP, DEPT ANESTHESIA, DK-2100 COPENHAGEN, DENMARK
来源
AMERICAN JOURNAL OF PHYSIOLOGY | 1994年 / 266卷 / 01期
关键词
CARDIOVASCULAR CONTROL; CENTRAL COMMAND; MUSCLE MECHANORECEPTORS; MUSCLE METABOREFLEX;
D O I
10.1152/ajpheart.1994.266.1.H79
中图分类号
Q4 [生理学];
学科分类号
071003 ;
摘要
To evaluate modulation of muscle sympathetic nerve activity (MSNA) during posthandgrip muscle ischemia (PHGMI), subjects performed 2 min of isometric handgrip at 33% of maximal voluntary contraction (MVC) followed by 2 min of PHGMI produced by forearm vascular occlusion. The response to PHGMI was studied in the absence and again during the addition of contralateral rhythmic handgrip (RHG; 40 times/min) at 15% (n = 6) and 30% (n = 10) MVC during the second minute of the PHGMI. Additionally, to isolate the effect of central command, response to PHGMI was studied during attempted RHG after sensory nerve blockade (n = 5). RHG for 2 min at 15 and 30% MVC and attempted RHG for 2 min did not increase MSNA. Isometric handgrip elicited an 130+/-48% increase in MSNA(P < 0.05), which was maintained during PHGMI. RHG at 15 and 30% MVC elicited an attenuation of MSNA (-10+/-7% and -14+/-6%, respectively) when performed during the second minute of PHGMI (P < 0.05). In contrast, attempted RHG did not significantly affect MSNA during PHGMI. The findings demonstrate modulation of MSNA during activation of the muscle metaboreflex. The attenuation of metaboreceptor-mediated increases in MSNA appear to be the result of mechanosensitive muscle afferents and not central command.
引用
收藏
页码:H79 / H83
页数:5
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