SYNAPTIC INTERACTIONS OF BARO- AND CHEMORECEPTOR NEURONS

神经化学解剖和突触的相互作用的途径， 控制压力和化学感受器反射的中枢神经系统 并不完全理解。 几个相互竞争的假设表明， 谷氨酸、P物质或神经肽Y可能是神经递质 包含在初级传入压力和化学感受器末梢中，和/或 孤束核二级心肺周核 （NTS）。 然而，没有超微结构的证据，这些假设。 另一种假说认为，NTS中的GABA能终末介导了 压力感受器反射的突触前抑制。 拟议 我们将使用电子显微镜免疫细胞化学研究， 胶体金和过氧化物酶组织化学，以获得超微结构 证明以下关键问题：1）什么是（是） 初级传入终末内所含的神经递质， 起源于颈动脉窦和颈动脉体， 化学感受器反射信息进入NTS？ 2)什么是（） NTS的二级神经元内所含的神经递质， 接收并传递压力和化学感受器信号 3)什么 NTS神经元内含有神经递质， 压力感受器传入末梢 这些实验将提供第一个 超微结构评价至少七个重要的假设， 压力和化学感受器反射的神经化学回路。 这些 数据将帮助我们理解影响人类行为的核心机制， 血压和呼吸。

The neurochemical anatomy and synaptic interactions of pathways in the central nervous system that control the baro- and chemoreceptor reflexes are incompletely understood. Several competing hypotheses indicate that glutamate, substance P, or neuropeptide Y may be the neurotransmitter(s) contained in primary afferent baro- and chemoreceptor terminals, and/or in second order cardiorespiratory perikarya in the nucleus tractus solitarius (NTS). However, there is no ultrastructural proof of these hypotheses. Another hypothesis suggests that GABAergic terminals in the NTS mediate presynaptic inhibition of the baroreceptor reflex. In the proposed research we will use electron microscopic immunocytochemistry with colloidal gold, and peroxidase histochemistry to obtain ultrastructural proof of the following critical questions: 1) What is (are) the neurotransmitter(s) contained within primary afferent terminals which originate in the carotid sinus and carotid body, and transmit baro- and chemoreceptor reflex information into the NTS? 2) What is (are) the neurotransmitter(s) contained within second order neurons of the NTS which receive and relay baro- and chemoreceptor signals? 3) What neurotransmitter(s) is (are) contained within NTS neurons which modulate baroreceptor afferent terminals? These experiments will provide the first ultrastructural evaluations of at least seven important hypotheses on the neurochemical circuitry of the baro- and chemoreceptor reflexes. These data will help us to understand the central mechanisms which influence blood pressure and respiration.