Hayes Shawn G, Kaufman Marc P
Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, California 95616, USA.
J Appl Physiol (1985). 2002 Apr;92(4):1628-34. doi: 10.1152/japplphysiol.00905.2001.
Although mesencephalic locomotor region (MLR) stimulation and the exercise pressor reflex have been shown to increase whole nerve renal sympathetic activity, it is not known whether these mechanisms converge onto the same population of renal sympathetic postganglionic efferents. In decerebrate cats, we examined the responses of single renal sympathetic postganglionic efferents to stimulation of the MLR and the exercise pressor reflex (i.e., static contraction of the triceps surae muscles). We found that, in most instances (24 of 28 fibers), either MLR stimulation or the muscle reflex, but not both, increased the discharge of renal postganglionic sympathetic efferents. In addition, we found that renal sympathetic efferents that responded to static contraction while the muscles were freely perfused responded more vigorously to static contraction during circulatory arrest. Moreover, stretch of the calcaneal (Achilles) tendon stimulated the same renal sympathetic efferents as did static contraction. These findings suggest that MLR stimulation and the exercise pressor reflex do not converge onto the same renal sympathetic postganglionic efferents.
尽管中脑运动区（MLR）刺激和运动升压反射已被证明可增加肾交感神经的全神经活动，但尚不清楚这些机制是否作用于同一群肾交感神经节后传出纤维。在去大脑猫中，我们研究了单个肾交感神经节后传出纤维对MLR刺激和运动升压反射（即腓肠肌静态收缩）的反应。我们发现，在大多数情况下（28根纤维中的24根），要么MLR刺激，要么肌肉反射，但不是两者同时，会增加肾节后交感神经传出纤维的放电。此外，我们发现，在肌肉自由灌注时对静态收缩有反应的肾交感神经传出纤维，在循环停止期间对静态收缩的反应更强烈。而且，跟腱（跟腱）的拉伸与静态收缩一样，刺激了相同的肾交感神经传出纤维。这些发现表明，MLR刺激和运动升压反射并不作用于同一群肾交感神经节后传出纤维。
