Parasympathetic control of the heart. III. Neuropeptide Y-immunoreactive nerve terminals synapse on three populations of negative chronotropic vagal preganglionic neurons
Parasympathetic control of the heart. III. Neuropeptide Y-immunoreactive nerve terminals synapse on three populations of negative chronotropic vagal preganglionic neurons
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DOI：
10.1152/japplphysiol.00621.2003
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发表时间：
2004-06-01
影响因子：
3.3
通讯作者：
Massari, VJ
中科院分区：
文献类型：
--
作者：
Gray, AL;Johnson, TA;Massari, VJ
心率的迷走神经节后控制由两个心内神经节介导，即，窦房（SA）和心房后（PA）神经节。目前还不清楚支配PA神经节的迷走神经节前神经元（VPN）或支配这些VPN的中枢传入神经的神经化学解剖。这些问题进行了检查，用光镜逆行标记方法和双标记电镜组织化学和免疫细胞化学方法。投射到PA神经节的VPN仅在腹外侧疑核（NA-VL）中的狭窄列中发现。这些神经元相对较大（37.6+/-2.7 mum × 21.3+/-3.4 mum），具有丰富的细胞质和细胞内细胞器，罕见的体细胞和树突棘，圆形未内陷的细胞核和有髓鞘的轴突。先前的生理数据表明，微量注射神经肽Y（NPY）到NA-VL引起负性变时效应。目前的形态学数据表明，NPY免疫反应阳性的神经末梢形成18+/-4%的轴树或轴体突触，并在投射到PA神经节的VPN上紧密并列。从SA和PA神经节逆行标记NA-VL中的三个近似相等的VPN群体。一个群体分别投射到SA神经节、PA神经节或SA和PA神经节。因此，在迷走神经节前对心率的控制中既有共享的又有独立的通路。这些数据与心率的中枢和外周副交感神经控制由多个潜在冗余和/或相互作用的通路和机制协调的假设一致。
The vagal postganglionic control of cardiac rate is mediated by two intracardiac ganglia, i.e., the sinoatrial (SA) and posterior atrial (PA) ganglia. Nothing is known about the vagal preganglionic neurons (VPNs) that innervate the PA ganglion or about the neurochemical anatomy of central afferents that innervate these VPNs. These issues were examined using light microscopic retrograde labeling methods and dual-labeling electron microscopic histochemical and immunocytochemical methods. VPNs projecting to the PA ganglion are found in a narrow column exclusively in the ventrolateral nucleus ambiguus (NA-VL). These neurons are relatively large (37.6+/-2.7 mum by 21.3+/-3.4 mum) with abundant cytoplasm and intracellular organelles, rare somatic and dendritic spines, round uninvaginated nuclei, and myelinated axons. Previous physiological data indicated that microinjections of neuropeptide Y (NPY) into the NA-VL cause negative chronotropic effects. The present morphological data demonstrate that NPY-immunoreactive nerve terminals formed 18+/-4% of the axodendritic or axosomatic synapses and close appositions on VPNs projecting to the PA ganglion. Three approximately equal populations of VPNs in the NA-VL were retrogradely labeled from the SA and PA ganglia. One population each projects to the SA ganglion, the PA ganglion, or to both the SA and PA ganglia. Therefore, there are both shared and independent pathways involved in the vagal preganglionic controls of cardiac rate. These data are consistent with the hypothesis that the central and peripheral parasympathetic controls of cardiac rate are coordinated by multiple potentially redundant and/or interacting pathways and mechanisms.