Muscle mechano sensitive receptors close to the myotendinous junction of the Achilles tendon elicit a pressor reflex
Muscle mechano sensitive receptors close to the myotendinous junction of the Achilles tendon elicit a pressor reflex
复制标题
DOI：
10.1152/japplphysiol.01344.2006
复制
发表时间：
2007-06-01
影响因子：
3.3
通讯作者：
Matsukawa, Kanji
中科院分区：
文献类型：
--
作者：
Nakamoto, Tomoko;Matsukawa, Kanji
通过激活运动肌肉中的机械敏感传入神经的反馈调节引起心血管和交感神经反应，这些反应跟随张力的发展，并且在静态收缩和被动拉伸之间几乎相同。然而，导致运动压力反射的机械感受器的精确位置仍然未知。为了验证机械感受器位于肌腱连接处周围以监测肌肉张力变化而不是肌肉长度变化的假设，我们研究了麻醉大鼠三头肌表面肌被动拉伸时的反射性心血管反应。全身注射钆，切断跟腱，局部注射利度多，进入肌腱连接处。钆（42 μ mol/kg iv）使被动拉伸时心率和平均动脉血压的升高幅度分别降低了36%和22% -26%，表明反射性心血管反应是通过刺激肌肉机械敏感受体引起的。在同一只大鼠中，切断的跟腱和完整的跟腱对被动拉伸的心血管反应没有不同，这表明任何机械感受器，终止于跟腱的较远部分，都没有促进反射性心血管反应。肌腱交界处注射利多康（体积，0.04-0.1 ml）可使拉伸引起的心率和平均动脉血压升高分别降低37% - 49%和27% -34%。我们得出的结论是，唤起反射性心血管反应的肌肉机械敏感受体至少部分位于或接近跟腱的肌腱交界处。
Feedback regulation by activation of mechanosensitive afferents in the exercising muscle causes the cardiovascular and sympathetic nerve responses, which follow tension development and are almost identical between static contraction and passive stretch. The precise location of the mechanoreceptors contributing to the exercise pressor reflex, however, remained unknown. To test the hypothesis that the mechanoreceptors will be located around the myotendinous junction to monitor a change in muscle tension than a change in muscle length, we examined the reflex cardiovascular responses to passive stretch of the triceps surae muscle in anesthetized rats with three interventions; systemic injection of gadolinium, cutting the Achilles tendon, and local injection of lidocame into the myotendinous junction. Gadolinium (42 mu mol/kg iv) blunted the increases in heart rate and mean arterial blood pressure during passive stretch by 36 and 22-26%, respectively, suggesting that the reflex cardiovascular responses were evoked by stimulation of muscle mechanosensitive receptors. The cardiovascular responses to passive stretch were not different between the cut Achilles tendon and the intact tendon in the same rats, suggesting that any mechanoreceptors, terminated in the more distal part of the tendon, did not contribute to the reflex cardiovascular responses. Lidocame (volume, 0.04-0.1 ml) injected into the myotendinous junction blunted the stretch-induced increases in heart rate and mean arterial blood pressure by 37-49 and 27-34%, respectively. We conclude that the muscle mechanosensitive receptors evoking the reflex cardiovascular responses at least partly locate at or close to the myotendinous junction of the Achilles tendon.