Immunohistochemical and biochemical analysis of serotonin and substance P colocalization in the nucleus tractus solitarii and associated afferent ganglia of the rat.
Immunohistochemical and biochemical analysis of serotonin and substance P colocalization in the nucleus tractus solitarii and associated afferent ganglia of the rat.
复制标题
对大鼠孤束核和相关传入神经节中血清素和 P 物质共定位的免疫组织化学和生化分析。
DOI：
10.1002/syn.890020309
复制
发表时间：
1988
期刊：
影响因子：
--
通讯作者：
Helke,CJ
中科院分区：
文献类型：
--
作者：
Thor,KB;Hill,KM;Harrod,C;Helke,CJ
前人对孤束核(NTS)传入投射的研究表明，中缝苍白核内半数以上逆行标记神经元含有5-羟色胺免疫反应阳性神经元，其中半数以上含有P物质免疫反应阳性神经元，提示这两种可能的神经递质共存于NTS传入神经元。本研究的目的是：(1)直接确定NTS、最后区(AP)和迷走神经背侧运动核(DMN)内的静脉曲张是否含有这两种递质；(2)确定结节和岩神经节中的初级传入神经元是否也可能同时定位5-羟色胺和P物质；(3)对5-羟色胺能曲张体内P物质的含量进行定量。5，7-二羟色胺-5，7-二羟色胺(5，7-DHT)核团和赋形剂处理组大鼠5-羟色胺能静脉曲张中P物质的含量用放射免疫分析法(RIA)测定。双标记曲张在NTS和DMN中很常见(即，在质量上与舌下核和颈髓前角的密度相似)；然而，这些自主神经区域的绝大多数曲张只对其中一个递质显示免疫反应。与单标记曲张的数量相比，双标记曲张的缺乏反映在5，7 DHT和赋形剂处理的大鼠NTS尾侧和中间水平的P物质水平没有显著下降。然而，在NTS的吻部水平，5，7 DHT处理的大鼠与赋形剂处理的大鼠相比，P物质水平显著降低(45%)。5，7-二羟色胺处理组大鼠吻侧NTS切片的免疫组织化学结果也显示P物质密度降低。结节和岩神经节的免疫组织化学研究显示有大量的5-羟色胺和P物质免疫阳性神经元，但没有一个神经元同时含有这两种递质。根据缺乏显示5-羟色胺和P物质共存的初级传入神经元，以及以前对含有5-羟色胺和P物质的NTS传入神经元的研究，似乎中缝尾侧延髓核是共同定位5-羟色胺和P物质的曲张的来源。虽然NTS和DMN的这些曲张的密度与脊髓前角的密度相当，但这只包括NTS和DMN中仅包含其中任何一种递质的一小部分曲张。
In a previous study of afferent projections to the nucleus tractus solitarii (NTS), it was shown that over half of the retrogradely‐labelled neurons in the nucleus raphe pallidus contained serotonin‐immunoreactivity and over half of these neurons contained substance P‐immunoreactivity, suggesting that these two putative neurotransmitters are colocalized in NTS‐affent neurons. The objectives of the present study were to (1) directly determine if varicosities in the NTS, the area postrema (AP), and the dorsal motor nucleus of the vagus nerve (DMN) do contain both transmitters, (2) determine if primary afferent neurons in the nodose and petrosal ganglia might also colocalize serotonin and substance P, and (3) quantify the amount of substance P that is contained in serotonergic varicosities in the NTS.Distributions and colocalization of substance P and serotonin in the NTS were studied using dual‐color immunohistochemistry, while the quantity of substance P in serotonergic varicosities was assessed by radioimmunoassay (RIA) using micropunches from the NTS of 5,7‐dihydroxytryptamine‐(5,7 DHT—) and vehicle‐treated rats.Varicosities that contained both serotonin‐ and substance P‐immunoreactivity were found in the NTS, the DMN, and the AP. Double‐labelled varicosities were common in the NTS and DMN (i.e., qualitatively similar to the density seen in the hypoglossal nucleus and in the ventral horn of the cervical spinal cord); however, the vast majority of the varicosities in these autonomic areas only displayed immunoreactivity for one or the other of these transmitters.This paucity of doubly‐labelled varicosities, in comparison to the number of singlylabelled varicosities, was reflected in the lack of a significant decrease in substance P levels as determined by RIA of micropunches taken from caudal and intermediate levels of the NTS in 5,7 DHT—and vehicle‐treated rats. At rostral levels of the NTS, however, there was a significant reduction (45%) in substance P levels in 5,7 DHT‐treated rats compared to vehicle‐treated rats. Immunohistochemical evaluation of sections from the rostral NTS of 5,7 DHT‐treated rats also indicated that the density of substance P varicosities was reduced.Immunohistochemical studies of the nodose and petrosal ganglia showed numerous serotonin‐ and substance P‐immunoreactive neurons, but none of the neurons contained immunoreactivity for both transmitters.In conclusion, serotonin and substance P are colocalized in varicosities in the NTS, the DMN, and the AP. Based upon the absence of primary afferent neurons that exhibit colocalization of serotonin and substance P, and previous studies of serotonin‐ and substance P‐containing NTS‐afferent neurons; it appears that the caudal medullary raphe nuclei are the source of varicosities that colocalize serotonin and substance P. While the density of these varicosities in the NTS and DMN are comparable to the density seen in the ventral horn of the spinal cord, this comprises only a small proportion of the varicosities in the NTS and DMN that contain either transmitter alone.