Functional roles of co-transmitters in brainsten cholinergic neurons

脑胆碱能神经元中共递质的功能作用

基本信息

批准号：
05680725
负责人：
KAYAMA Yukihiko
金额：
$ 1.34万
依托单位：
Fukushima Medical College
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05680725/
关键词：
laterodorsal tegmental nucleus acetylcholine substance P nitric oxide co-transmitters thalamus cerebral blood flow ascending activating system 外側膝状核レーザードプラ血流計

项目摘要

Cholinergic neurons gathering tightly in the laterodorsal tegmental nucleus (LDT) of the brainstem have nitric oxide (NO) and/or substance P (SP) as co-transmitters. The present study examined whether these co-transmitters released from axon terminals or varicosities, and what effects they gave to postsynaptic targets.In the previous study we had shown that LDT stimulation produced excitation of thalamic relay neurons which received direct projection of the cholinergic neurons. We examined in urethane-anesthetized rats, using a laser-Doppler flow meter, how the same LDT stimulation affected cerebral blood flow in the thalamus, since the co-transmitters have strong action on the blood vessels. An increase of the blood flow was observed consistently starting within several seconds after the onset of LDT stimulation and continuing about 1 minute after the stimulation. The increase was reduced by administration of scopolamine, a muscarinic antagonist, but the treatment did not block it com … More pletely.Whether NO concentration in the thalamus increased after the LDT stimulation was also examined in urethane-anesthetized rats, using electrochemical electrode sensitive specifically to NO (developed in Shionogi Research Laboratories) . The NO concentration increased transiently just after the stimulation only when the stimulating electrode was inserted in the LDT ; the stronger stimulation produced the stronger increase. The results show that NO is released from the axon terminals and/or varicosities by the excitation of LDT neurons.Postsynaptic actions of the co-transmitters were examined in in vitro slice preparations of the rat thalamus. Most thalamic neurons were depolarized by application of acetylcholine (ACh) . When SP was applied simultaneously with ACh, the depolarization was increased in some neurons, but was cancelled to produce no resting potential change in others. It is thus suggested that SP as a co-transmitter modifies the action of main transmitter ACh, but tha modification differs from neuron to neuron. Actions of NO was not demonstrated clearly. Less

紧密聚集在脑干后背侧被盖核 (LDT) 中的胆碱能神经元具有一氧化氮 (NO) 和/或 P 物质 (SP) 作为共递质。本研究检查了这些共递质是否从轴突末端或静脉曲张释放。以及它们对突触后目标产生什么影响。在之前的研究中，我们已经表明 LDT 刺激会产生丘脑中继神经元的兴奋，这些神经元接受直接投射我们使用激光多普勒流量计在氨基甲酸乙酯麻醉的大鼠中检查了相同的 LDT 刺激如何影响丘脑的脑血流，因为共递质对血管有强烈的作用，导致血管增加。观察到血流始终在 LDT 刺激开始后几秒钟内开始，并在刺激后持续约 1 分钟。给予东莨菪碱（一种毒蕈碱拮抗剂）可减少血流的增加，但治疗后。并没有完全阻断它。在乌拉坦麻醉的大鼠中，使用对 NO 特异性敏感的电化学电极（盐野木研究实验室开发），检查了 LDT 刺激后丘脑中的 NO 浓度是否增加。NO 浓度只是短暂增加。刺激后，只有当刺激电极插入LDT时，刺激越强，NO从轴突末端和/或静脉曲张中释放得越强。在大鼠丘脑的体外切片制剂中检查了共递质的突触后作用，大多数丘脑神经元通过应用乙酰胆碱（ACh）而去极化。在一些神经元中增加，但在其他神经元中被取消而不会产生静息电位变化，因此表明 SP 作为共递质改变了主要的作用。神经元之间的修饰不同，但 NO 的作用并不明显。