Lendvai B, Sershen H, Lajtha A, Santha E, Baranyi M, Vizi E S
Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.
Neuropharmacology. 1996;35(12):1769-77. doi: 10.1016/s0028-3908(96)00115-3.
In the present study we investigated the effect of different nicotinic agonists (dimethylphenyl-piperazinium-iodide (DMPP), (-)nicotine, cytisine, (-)-lobeline, and (-)epibatidine) and antagonists (mecamylamine and dihydro-beta-erythroidine) on the release of [3H]5-HT from hippocampal slices. The nicotinic agonists DMPP and lobeline and electrical field stimulation, released [3H]5-HT from the hippocampus; other nicotinic agonists, such as (-)-nicotine, cytisine, and (-)-epibatidine had no effect. Unlike lobeline-induced release of [3H]5-HT, the effect of DMPP (10 and 40 microM) was antagonized by mecamylamine (20 and 10 microM). The effect of DMPP was [Ca2+]o-independent. In experiments carried out at 7 degrees C, i.e. the membrane carrier proteins are inhibited and the release by lobeline was abolished while the DMPP-induced release of 5-HT was rather potentiated. It is proposed that the effect of DMPP and lobeline, to enhance the release of [3H]5-HT from the hippocampus, was mediated by two different mechanisms. While DMPP-induced 5-HT release can be linked to a non-classical nAChR activation ([Ca2+]o-independence), the effect of lobeline was likely mediated by uptake carriers.
在本研究中，我们研究了不同烟碱激动剂（碘化二甲基苯基哌嗪（DMPP）、（-）尼古丁、金雀花碱、（-）洛贝林和（-）埃博霉素）和拮抗剂（美加明和二氢β-刺桐啶）对海马切片中[3H]5-羟色胺（5-HT）释放的影响。烟碱激动剂DMPP和洛贝林以及电场刺激可使海马释放[3H]5-HT；其他烟碱激动剂，如（-）尼古丁、金雀花碱和（-）埃博霉素则无此作用。与洛贝林诱导的[3H]5-HT释放不同，美加明（20和10 microM）可拮抗DMPP（10和40 microM）的作用。DMPP的作用不依赖于细胞外钙离子浓度（[Ca2+]o）。在7摄氏度下进行的实验中，即膜载体蛋白受到抑制，洛贝林诱导的释放被消除，而DMPP诱导的5-HT释放反而增强。有人提出，DMPP和洛贝林增强海马中[3H]5-HT释放的作用是由两种不同机制介导的。虽然DMPP诱导的5-HT释放可能与非经典烟碱型乙酰胆碱受体（nAChR）激活有关（不依赖于[Ca2+]o），但洛贝林的作用可能是由摄取载体介导的。
