Tokizawa Ken, Mizuno Masaki, Muraoka Isao
Graduate School of Sport Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama, Japan.
Exp Physiol. 2006 Jul;91(4):723-9. doi: 10.1113/expphysiol.2006.033589. Epub 2006 Apr 27.
Our previous studies showed that venous occlusion or passive stretch of the lower limb, assuming a mechanical stimulus, attenuates the vasoconstriction in the non-exercised forearm during postexercise muscle ischaemia (PEMI) of the upper limb. In this study, we investigated whether a metabolic stimulus to the lower limb induces a similar response. Eight subjects performed a 2 min static handgrip exercise at 30% maximal voluntary contraction (MVC) followed by 3 min PEMI of the upper limb, concomitant with or without 2 min static ankle dorsiflexion at 30% MVC followed by 2 min PEMI of the lower limb. During PEMI of the upper limb alone, forearm blood flow (FBF) and forearm vascular conductance (FVC) in the non-exercised arm decreased significantly, whereas during combined PEMI of the upper and lower limbs, the decreases in FBF and FVC produced by PEMI of the upper limb was attenuated. Forearm blood flow and FVC were significantly greater during combined PEMI of the upper and lower limbs than during PEMI of the upper limb alone. When PEMI of the lower limb was released after combined PEMI of the upper and lower limbs (only PEMI of the upper limb was maintained continuously), the attenuated decreases in FBF and FVC observed during combined PEMI of the upper and lower limbs was not observed. Thus, forearm vascular responses differ when muscle metaboreceptors are activated in the upper limb and when there is combined activation of muscle metaboreceptors in both the upper and lower limbs.
我们之前的研究表明，假设存在机械刺激，下肢的静脉闭塞或被动拉伸会减弱上肢运动后肌肉缺血（PEMI）期间未运动前臂的血管收缩。在本研究中，我们调查了对下肢的代谢刺激是否会引发类似反应。八名受试者以最大自主收缩（MVC）的30%进行2分钟的静态握力运动，随后上肢进行3分钟的PEMI，同时伴有或不伴有以MVC的30%进行2分钟的静态踝关节背屈，随后下肢进行2分钟的PEMI。仅在上肢进行PEMI期间，未运动手臂的前臂血流量（FBF）和前臂血管传导率（FVC）显著下降，而在上肢和下肢联合进行PEMI期间，上肢PEMI导致的FBF和FVC下降有所减弱。上肢和下肢联合进行PEMI期间的前臂血流量和FVC显著高于仅上肢进行PEMI期间。当上肢和下肢联合进行PEMI后释放下肢的PEMI（仅持续维持上肢的PEMI）时，未观察到在上肢和下肢联合进行PEMI期间所观察到的FBF和FVC的减弱下降。因此，当上肢的肌肉代谢感受器被激活时以及当上肢和下肢的肌肉代谢感受器同时被激活时，前臂的血管反应是不同的。
