Involvement of medullary GABAergic and serotonergic raphe neurons in respiratory control: Electrophysiological and immunohistochemical studies in rats
Involvement of medullary GABAergic and serotonergic raphe neurons in respiratory control: Electrophysiological and immunohistochemical studies in rats
复制标题
DOI：
10.1016/j.neures.2006.08.001
复制
发表时间：
2006-11-01
影响因子：
2.9
通讯作者：
Aoki, Mamoru
中科院分区：
文献类型：
--
作者：
Cao, Ying;Matsuyama, Kiyoji;Aoki, Mamoru
在本研究中，我们首先研究了假定的神经递质γ -氨基丁酸（GABA）和血清素（5-HT）在rape诱导的大鼠呼吸活动的促进或抑制作用中的可能参与。其次，我们研究了garaergy和5 -羟色胺能神经元从中脑髓核向膈运动核（PMN）的脊髓投射的可能性。我们观察到静脉注射(+)-双管碱，一种GABA(a)受体拮抗剂，显著减少电刺激中缝大肌（RM）或中缝暗肌（RO）引起的呼吸抑制。另一方面，静脉注射methysergide（一种广谱5-HT受体拮抗剂）可显著降低中脑苍白部（RP）或RO电刺激引起的呼吸促进。通过在PMN区C4和C5段注射Texas Red逆行示踪和免疫组织化学标记相结合的方法，我们观察到免疫阳性和Texas Red双标记的神经元主要定位于RM，另外也定位于RO。然而，5-HT免疫阳性和德克萨斯红双标记神经元主要定位于RP，此外还有RO和RM。这些发现表明，RM-或ro诱导的抑制作用至少部分通过直接的gaba能下降途径传递到PMN。然而，RP-或ro -诱导的大鼠促进作用是通过血清素能下降途径传播的。(c) 2006年爱思唯尔爱尔兰有限公司和日本神经科学学会。版权所有。
In the present study we first examined the possible involvement of the putative neurotransmitters gamma-aminobutyric acid (GABA) and serotonin (5-HT) in raphe-induced facilitatory or inhibitory effects on the respiratory activity of rats. Secondly, we investigated the possibility of spinal projections of GARAergic and serotonergic neurons from the medullary raphe nuclei to the phrenic motor nucleus (PMN). We observed that an intravenous (i.v.) injection of (+)-bicuculline, a GABA(A) receptor antagonist, significantly reduced respiratory inhibition induced by electrical stimulation of the raphe magnus (RM) or the raphe obscurus (RO). On the other hand, an i.v. injection of methysergide, a broad-spectrum 5-HT receptor antagonist, significantly reduced the respiratory facilitation induced by electrical stimulation of the raphe pallidus (RP) or RO. By using a combined method of retrograde tracing with Texas Red injected into the PMN region at segments C4 and C5 and immunohistochemical labeling, we observed that glutamic acid decarboxylase (GAD; a GABA synthesizing enzyme) immunopositive and Texas Red double labeled neurons were predominantly localized in the RM, and additionally in the RO. However 5-HT immunopositive and Texas Red double-labeled neurons were predominantly localized in the RP, and additionally in the RO and RM. These findings suggest that RM-, or RO-induced inhibitory effects, are transmitted, at least in part, to the PMN via a direct GABAergic descending pathway. The RP-, or RO-induced facilitatory effects in rats however, are transmitted via a serotonergic descending pathway. (c) 2006 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.