Dorsal raphe nucleus serotonergic neurons innervate the rostral ventrolateral medulla in rat
Dorsal raphe nucleus serotonergic neurons innervate the rostral ventrolateral medulla in rat
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DOI：
10.1016/s0006-8993(99)01181-6
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发表时间：
1999-04-03
期刊：
影响因子：
2.9
通讯作者：
Mann, JJ
中科院分区：
文献类型：
--
作者：
Underwood, MD;Arango, V;Mann, JJ
刺激中缝背核（DRN）可以改变动脉压、心率和脑血流量，但DRN到延髓自主神经核的投射尚未被描述。我们研究了DRN的5-HT投射是否终止于延髓头端腹外侧区（RVL），如果是，投射是否介导DRN刺激引起的心血管反应。在成年雄性Sprague-Dawley大鼠中进行研究。将辣根过氧化物酶或霍乱毒素B单侧或双侧注入RVL。5-HT，其前体L-色氨酸和5-羟色氨酸和代谢产物5-羟吲哚乙酸的水平进行了测量，在腹侧延髓的HPLC三周后，放置在DRN电解病变。5-羟色胺转运蛋白（H-3-氰基丙咪嗪结合）定量放射自显影DRN损伤的动物。辣根过氧化物酶或霍乱毒素B注射到延髓水平的RVL导致逆行标记的神经元双边，同侧优势，在DRN。标记的细胞占优势，在吻腹外侧部分的DRN，但也观察到在背侧，外侧和束间DRN亚核;较少的神经元，观察到在尾部的DRN。在DRN放置电解损伤后三周，与假手术或未手术对照组相比，髓质中5-HT和5-羟基吲哚乙酸的浓度分别降低了45%和48%，但L-色氨酸或5-羟基色氨酸的浓度没有降低。DRN病变减少了约30%的5-羟色胺转运蛋白在RVL的结合相比，unlestered控制。单侧RVL损伤使诱发的血压反应降低53 +/- 15%;双侧RVL损伤使反应降低86 +/-9%。在单侧或双侧RVL损伤后，DRN刺激引起的皮质血流量增加没有变化。这些研究表明，从DRN到RVL有一个下行的多巴胺能投射。这种投射可能介导由DRN刺激引起的自主神经变化。(C)1999 Elsevier Science B. V.保留所有权利。
Stimulation of the dorsal raphe nucleus (DRN) alters arterial pressure, heart rate and cerebral blood flow, yet projections from the DRN to medullary autonomic nuclei have not been described. We examined whether serotonergic (5-HT) projections from the DRN terminate in the rostral ventrolateral medulla (RVL) and if so, whether the projection mediates cardiovascular responses to DRN stimulation. Studies were performed in adult male Sprague-Dawley rats. Horseradish peroxidase or choleratoxin B was injected unilaterally or bilaterally into the RVL. Levels of 5-HT, its precursors L-tryptophan and 5-hydroxytryptophan and the metabolite 5-hydroxyindole acetic acid were measured in the ventral medulla by HPLC three weeks following placement of electrolytic lesions in DRN. Serotonin transporter (H-3-cyanoimipramine binding) was quantified by autoradiography in DRN-lesioned animals. Horseradish peroxidase or choleratoxin B injections into the medulla at the level of the RVL resulted in retrogradely labeled neurons bilaterally, with ipsilateral predominance, in the DRN. Labeled cells were preponderant in rostral ventrolateral portions of the DRN, but were also observed in the dorsal, lateral and interfascicular DRN subnuclei; fewer neurons were observed in caudal portions of the DRN. Three weeks following placement of electrolytic lesions in the DRN, the concentrations of 5-HT and 5-hydroxyindole acetic acid, but not L-tryptophan or 5-hydroxytryptophan, were reduced in the medulla by 45 and 48%, respectively, compared to sham-operated or unoperated controls. DRN lesions reduced binding to the 5-HT transporter in the RVL by approximately 30% compared to unlesioned controls. Unilateral lesions of the RVL reduced the evoked blood pressure response by 53 +/- 15%; bilateral RVL lesions reduced the response by 86 +/- 9%. The increase in cortical blood flow elicited by DRN stimulation was unchanged after unilateral or bilateral RVL lesions. These studies demonstrate that there is a descending serotonergic projection from the DRN to the RVL. This projection may mediate autonomic changes elicited by DRN stimulation. (C) 1999 Elsevier Science B.V. All rights reserved.