Substance P nerve terminals synapse upon negative chronotropic vagal motoneurons.
Substance P nerve terminals synapse upon negative chronotropic vagal motoneurons.
复制标题
P物质神经末梢突触位于负变时性迷走神经运动神经元上。
DOI：
10.1016/0006-8993(94)91300-5
复制
发表时间：
1994
期刊：
影响因子：
2.9
通讯作者：
Gatti,PJ
中科院分区：
文献类型：
--
作者：
Massari,VJ;Johnson,TA;Llewellyn-Smith,IJ;Gatti,PJ
先前的数据表明，在心脏表面上存在解剖学上分离的和生理上独立的副交感神经节，其能够选择性地控制窦房率、房室传导和心房收缩性。我们将逆行示踪剂注射到选择性调节心率的心神经节（SA神经节）。延髓组织进行处理的逆行标记的神经元的组织化学可视化和神经递质P物质（SP）的免疫组化检测的双重标记光镜和电镜方法。在疑腹外侧核（NA-VL）的最后区水平上有一细长柱状的负变时性逆行标记细胞。这些细胞被发现双边，但他们是不对称分布。一半的动物在逆行标记中表现出明显的右侧优势，而另一半的动物表现出较少的左侧优势。这些观察结果可能有助于解释文献中关于左右迷走神经对窦性心率的相对影响的一些争议。超微结构检查显示SP神经末梢和逆行标记的负性变时性NA-VL神经元之间存在轴-体和轴-树突接触。SP免疫反应通常与形成对称或不对称突触的终末中的大致密核心囊泡有关。这些观察结果提供了一个潜在的解剖基板的中枢介导的心动过缓引起的微量注射SP到NA。SP阳性终末与NA-VL区未标记神经元形成轴-体、轴-树、轴-轴突触。这些数据表明，SP也可以调节其他迷走神经节前神经元的活动。
Previous data indicate that there are anatomically segregated and physiologically independent parasympathetic ganglia on the surface of the heart which are capable of selective control of sino-atrial rate, atrio-ventricular conduction, and atrial contractility. We have injected a retrograde tracer into the cardiac ganglion which selectively regulates heart rate (the SA ganglion). Medullary tissues were processed for the histochemical visualization of retrogradely labeled neurons and for the immunohistochemical detection of the neurotransmitter substance P (SP) by dual labeling light and electron microscopic methods. Negative chronotropic retrogradely labeled cells were found in a long slender column in the ventrolateral nucleus ambiguus (NA-VL) which enlarged somewhat at the level of the area postrema. These cells were found bilaterally, but they were asymmetrically distributed. Half the animals showed a pronouncedrightside predominance in retrograde labeling, while the other half of the animals showed a lesserleftside predominance. These observations may help to explain some of the controversy in the literature concerning the relative influence of the right and left vagus nerves on sinus rate. Ultrastructural examination demonstrated axo-somatic and axo-dendritic contacts between SP nerve terminals and retrogradely labeled negative chronotropic NA-VL neurons. SP immunoreactivity was often associated with large dense-core vesicles in terminals forming either symmetric or asymmetric synapses. These observations provide a potential anatomical substrate for the centrally mediated bradycardia elicited by microinjections of SP into the NA. SP immunoreactive terminals were also observed to make axo-somatic, axo-dendritic, and axo-axonic synapses with unlabeled neurons in NA-VL. These data suggest that SP may also modulate the activity of other vagal preganglionic neurons.