5-hydroxytryptamine action in the rat olfactory bulb:: In vitro electrophysiological patch-clamp recordings of juxtaglomerular and mitral cells
5-hydroxytryptamine action in the rat olfactory bulb:: In vitro electrophysiological patch-clamp recordings of juxtaglomerular and mitral cells
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DOI：
10.1016/j.neuroscience.2004.10.034
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发表时间：
2005-01-01
期刊：
影响因子：
3.3
通讯作者：
Duchamp-Viret, P
中科院分区：
文献类型：
--
作者：
Hardy, A;Palouzier-Paulignan, B;Duchamp-Viret, P
嗅球是嗅觉通路的第一个中继，由源自中缝核的5 -羟色胺能离心纤维密集支配。虽然据报道5 -羟色胺神经支配参与哺乳动物的嗅觉学习，但这种神经递质对其假定的细胞目标的作用从未通过单一记录描述过。由于缺乏数据，本研究利用嗅球切片的全细胞记录分析了5HT对球旁细胞和二尖瓣细胞的影响。血清素使525个JG细胞中的34%去极化。一项对肾小球旁细胞特征的多元统计分析表明，5 -羟色胺反应细胞组在直流电注射下的张力放电模式、超极化激活阳离子电流的低表达和低膜容量等方面可以个体化。离子通道阻滞剂和斜坡电压方案的使用表明，肾小球旁细胞的5 -羟色胺能去极化可能是由于具有-44 mV逆转电位的非选择性阳离子电流。5 -羟色胺受体拮抗剂和激动剂药理试验表明，5HT对肾结石旁细胞的作用主要是由5HT（2C）受体介导的。在二尖瓣细胞中，血清素作用于242个测试细胞中的49.1%，诱导两种类型的反应。第一组二尖瓣细胞（26.8%,n=65）被血清素过度极化。这种反应可能是GABA对GABA(A)受体的间接介导的，因为它被双核碱拮抗。所涉及的gaba能神经元假设为球旁细胞和颗粒细胞，血清素主要通过5HT（2C）和5HT（2A）受体分别作用于这些细胞。第二组二尖瓣细胞（22.3%,n=54）被血清素通过5HT2A受体直接去极化。我们关于血清素作用于球旁细胞和二尖瓣细胞的数据揭示了血清素作用于嗅球网络的部分功能机制。这有望丰富其在嗅觉学习中的决定性作用的理解。(c) 2005 IBRO。Elsevier Ltd.出版。版权所有。
The olfactory bulb, first relay of olfactory pathways, is densely innervated by serotoninergic centrifugal fibers originating from the raphe nuclei. Although serotonin innervation was reported to be involved in olfactory learning in mammals, the action of this neurotransmitter on its putative cellular targets has been never described through unitary recordings. This lack of data initiated the present study where the effects of 5HT on juxtaglomerular and mitral cells are analyzed using whole-cell recordings on olfactory bulb slices.Serotonin depolarizes 34% of 525 JG cells. A multivariate statistical analysis of juxtaglomerular cells characteristics shows that the serotonin responsive cell group can be individualized regarding their tonic discharge-mode in response to a direct current injection, their lower expression of hyperpolarization-activated cation current and their low membrane capacities. The use of ion channel blockers and ramp voltage protocol indicate that serotoninergic depolarization of juxtaglomerular cells may be due to a nonselective cation current with a reversal potential of -44 mV. Pharmacological tests with serotonin receptor antagonists and agonists reveal that 5HT action on juxtaglomerular cells would be mainly mediated by 5HT(2C) receptors.In mitral cells, serotonin acts on 49.1% of the 242 tested cells, inducing two types of responses. A first subset of mitral cells (26.8%, n=65) were hyperpolarized by serotonin. This response would be indirect and mediated by action of GABA on GABA(A) receptors since it was antagonized by bicuculline. The involved GABAergic neurons are hypothesized to be juxtaglomerular and granular cells, on which serotonin would act mainly via 5HT(2C) and via 5HT(2A) receptors respectively. The second subset of mitral cells (22.3%, n=54) were directly depolarized by serotonin acting through 5HT2A receptors.Our data on serotonin action on juxtaglomerular cells and mitral cells reveal a part of functional mechanisms whereby serotonin can act on olfactory bulb network. This is expected to enrich the understanding of its determining role in olfactory learning. (c) 2005 IBRO. Published by Elsevier Ltd. All rights reserved.