Negrão C E, Trombetta I C, Batalha L T, Ribeiro M M, Rondon M U, Tinucci T, Forjaz C L, Barretto A C, Halpern A, Villares S M
Heart Institute (InCor), São Paulo, Cep 05403-000 Brazil.
Am J Physiol Heart Circ Physiol. 2001 Aug;281(2):H469-75. doi: 10.1152/ajpheart.2001.281.2.H469.
There is no information about the muscle metaboreflex control in obese individuals. In 40 normotensive obese women (OW; body mass index 33.5 +/- 0.4 kg/m2, age 32.4 +/- 1.1 yr) and 15 age-matched, normotensive lean women (LW; body mass index 22.7 +/- 0.8 kg/m2, age 34.4 +/- 1.4 yr), we measured muscle sympathetic nerve activity (MSNA) and forearm blood flow (FBF) in the nonexercising forearm during static exercise at 10 and 30% of maximal voluntary contraction (MVC). Baseline MSNA (38 +/- 2 vs. 31 +/- 1 bursts/min, P = 0.001) and mean blood pressure were significantly higher in OW compared with LW. FBF was significantly lower, whereas forearm vascular resistance was significantly higher in OW. During 10% MVC, MSNA increased similarly in both groups, but during 30% MVC, MSNA was higher in LW. FBF and forearm vascular resistance responses during both 10 and 30% MVC were similar between groups. During posthandgrip circulatory arrest, MSNA remained significantly elevated compared with baseline in both groups, but this increase was significantly lower in OW (3.8 +/- 0.82 vs. 9.4 +/- 1.03 bursts/min, P = 0.002). In conclusion, muscle metaboreflex control of MSNA is blunted in OW. MSNA responses are not augmented during selective activation of central command/mechanoreceptors and metaboreceptors, despite increased MSNA levels in OW. Muscle vasodilatory response during graded handgrip isometric exercise is preserved in OW.
目前尚无关于肥胖个体肌肉代谢性反射控制的信息。在40名血压正常的肥胖女性（OW；体重指数33.5±0.4kg/m²，年龄32.4±1.1岁）和15名年龄匹配、血压正常的瘦女性（LW；体重指数22.7±0.8kg/m²，年龄34.4±1.4岁）中，我们测量了在最大自主收缩（MVC）的10%和30%进行静态运动时，非运动前臂的肌肉交感神经活动（MSNA）和前臂血流量（FBF）。与LW相比，OW的基线MSNA（38±2次/分钟对31±1次/分钟，P = 0.001）和平均血压显著更高。OW的FBF显著更低，而前臂血管阻力显著更高。在10%MVC期间，两组的MSNA均有相似程度的增加，但在30%MVC期间，LW的MSNA更高。两组在10%和30%MVC期间的FBF和前臂血管阻力反应相似。在握力后循环停止期间，两组的MSNA均较基线显著升高，但OW的这种升高显著更低（3.8±0.82次/分钟对9.4±1.03次/分钟，P = 0.002）。总之，OW中MSNA的肌肉代谢性反射控制减弱。尽管OW的MSNA水平升高，但在中枢指令/机械感受器和代谢感受器选择性激活期间，MSNA反应并未增强。OW在分级握力等长运动期间的肌肉血管舒张反应得以保留。
