Clement M E, McCall R B
Cardiovascular Disease Research, Upjohn Company, Kalamazoo, MI 49001.
Brain Res. 1991 Mar 1;542(2):205-11. doi: 10.1016/0006-8993(91)91568-l.
In the present study we investigated the characteristics of medullary raphe serotonergic neurons. Specifically, we sought to examine further the similarities between medullospinal 5-HT neurons and the more extensively studied neurons of the dorsal raphe. Intravenous administration of 5-methoxy-dimethyltryptamine (5-MeODMT) produced a dose-related inhibition of the firing of midline medullary 5-HT neurons. Microiontophoretically applied 5-MeODMT also inhibited medullary 5-HT neurons. The inhibitory potency of 5-MeODMT was nearly identical to that observed for dorsal raphe 5-HT neurons. Microiontophoretic or intravenous administration of the 5-HT2 receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) did not alter the firing rate of medullary 5-HT neurons. Intravenous administration of the alpha 1-receptor antagonist prazosin resulted in an inhibition of the medullary 5-HT neuronal firing. The discharge of medullary 5-HT neurons increased during iontophoresis of norepinephrine. These data are discussed in relation to the identification and characterization of medullary 5-HT neurons. In addition, the data suggest that the firing rate of medullary 5-HT neurons is regulated in part by a tonic excitatory noradrenergic input.
在本研究中，我们调查了延髓中缝5-羟色胺能神经元的特征。具体而言，我们试图进一步研究延髓脊髓5-羟色胺（5-HT）神经元与研究更为广泛的中缝背核神经元之间的相似性。静脉注射5-甲氧基-二甲基色胺（5-MeODMT）可产生与剂量相关的对延髓中线5-HT神经元放电的抑制作用。微量离子电泳施加5-MeODMT也可抑制延髓5-HT神经元。5-MeODMT的抑制效力与中缝背核5-HT神经元所观察到的几乎相同。微量离子电泳或静脉注射5-HT2受体激动剂1-（2,5-二甲氧基-4-碘苯基）-2-氨基丙烷（DOI）不会改变延髓5-HT神经元的放电频率。静脉注射α1受体拮抗剂哌唑嗪可导致延髓5-HT神经元放电受到抑制。在去甲肾上腺素进行离子电泳期间，延髓5-HT神经元的放电增加。这些数据结合延髓5-HT神经元的识别和特征进行了讨论。此外，数据表明延髓5-HT神经元的放电频率部分受去甲肾上腺素能紧张性兴奋性输入的调节。
