Differential sympathetic reflex control in excerise

运动中交感神经反射的差异控制

• 批准号: 7049592
• 负责人: Marc Peter Kaufman
• 金额: $ 32.56万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2007-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7049592
• 关键词: afferent nerve; baroreceptors; baroreflex; blood pressure; blood vessel occlusion; cats; decerebration; exercise; gadolinium; heart rate; hexamethonium compound; kidney; muscle contraction; neuroregulation; postganglionic fiber; purinergic receptor; receptor expression; skin; striated muscles; sympathetic nervous system; vitamin B6; vitamin analog

DESCRIPTION (provided by applicant): The exercise pressor reflex is widely believed to play an important rote in controlling the sympathetic outflow to the vasculature during exercise in both humans and animals. The reflex is believed to arise from contracting skeletal muscles and is evoked by two types of stimuli, namely mechanical and metabolic. The sensory arm of the exercise pressor reflex arc is comprised of group III and IV fibers, which together haw been termed thin fiber muscle afferents.. Group I and II fibers do not participate in evoking this reflex. Although the role played the exercise pressor reflex in increasing arterial blood pressure during exercis, is well established, its control of the sympathetic outflow to specific visceral and somatic structures controversial. This is especially the case for the role played by metaboreceptors in reflexly activating the sympathetic outflow to the vasculature of the skin. In addition, the specific roles played by thin fiber mechanoreceptors and metaboreceptors in activating the sympathetic outflow to the skeletal muscles and the kidney are unknown. The experiments proposed in this application will determine the effect of blocking the contractioninduced input from thin fiber muscle mechanoreceptors and metaboreceptors on the responses of single fiber sympathetic postganglionic efferent fibers innervating the vasculature of hind limb hairy skin, the vasculature of hind limb skeletal muscle and the kidney. Mechanoreceptor input arising from the triceps surae muscles of decerebrate unanesthetized cats will be prevented by popliteal arterial injections of gadolinium, an agent which blocks mechanogated channels. Metaboreceptor input from these muscles will be blocked by popliteal arterial injections of PPADS, a purinergic 2 receptor antagonist. The sympathetic nature of the efferent discharge will be identified by: 1.) showing that the efferents are activated by an electrical pulse applied to the thoracic or lumbar sympathetic chain; 2.) showing that both spontaneous and evoked activity is prevented by ganglionic blockade with hexamethonium; and 3.) showing that the activity of the renal, muscle and to a lesser extent, skin sympathetic discharge is under control of the arterial baroreceptors. The proposed experiments will provide new information about the role played by thin fiber muscle mechanoreceptors and metaboreceptors in controlling the sympathetic outflow during exercise.

描述（由申请人提供）：人们普遍认为，运动加压反射在人类和动物运动期间控制交感神经流向脉管系统方面发挥着重要作用。 这种反射被认为是由骨骼肌收缩引起的，由两种类型的刺激引起，即机械刺激和代谢刺激。 运动加压反射弧的感觉臂由第 III 组和第 IV 组纤维组成，它们一起被称为细纤维肌肉传入。第 I 组和 II 组纤维不参与诱发这种反射。 尽管运动升压反射在运动期间增加动脉血压中所发挥的作用已得到充分证实，但其对特定内脏和躯体结构的交感神经流出的控制仍存在争议。 对于代谢感受器在反射性激活皮肤脉管系统交感神经流出方面所发挥的作用尤其如此。 此外，细纤维机械感受器和代谢感受器在激活骨骼肌和肾脏的交感神经流出中所起的具体作用尚不清楚。 本申请中提出的实验将确定阻断来自细纤维肌肉机械感受器和代谢感受器的收缩诱导输入对支配后肢毛状皮肤的脉管系统、后肢骨骼肌的脉管系统和单纤维交感神经节后传出纤维的反应的影响。肾。 腘动脉注射钆（一种阻断机械通道的药物）可以阻止去大脑未麻醉猫的小腿三头肌产生的机械感受器输入。 来自这些肌肉的代谢感受器输入将被腘动脉注射 PPADS（一种嘌呤 2 受体拮抗剂）所阻断。 传出神经放电的交感神经性质可通过以下方式识别： 1.) 显示传出神经是由施加到胸椎或腰椎交感链的电脉冲激活的； 2.)表明用六甲铵阻断神经节可阻止自发活动和诱发活动； 3.)表明肾脏、肌肉的活动以及较小程度的皮肤交感神经放电均受到动脉压力感受器的控制。 所提出的实验将提供有关细纤维肌肉机械感受器和代谢感受器在运动过程中控制交感神经流出中所发挥的作用的新信息。