Effects of GABA,dopamine, and substance P on the release of newly synthesized 3H-5-hydroxytryptamine from rat substantia nigra in vitro |
| |
Authors: | J C Reubi P C Emson T M Jessell L L Iversen |
| |
Institution: | (1) MRC Neurochemical Pharmacology Unit, Department of Pharmacology, Medical School, Hills Road, CB2 2QD Cambridge, UK;(2) Present address: Brain Research Institute, University of Zürich, Zürich;(3) Present address: Department of Pharmacology, Harvard Medical School, Boston, Mass., USA |
| |
Abstract: | Summary The effects of GABA, substance P and dopamine on the release of newly synthesized 3H-5-HT were investigated, using slices of rat substantia nigra superfused with l-3H-tryptophan in vitro. GABA (50 M) had no inhibitory effect on the potassium-evoked-release of 3H-5-HT. Substance P (50 M) and eledoisin (50 M) stimulated the spontaneous release of 3H-5-HT. This effect seems to be indirect and is possibly mediated by dopaminergic neurones, since the dopamine antagonist drug -flupenthixol (1 M) abolished the substance P-evoked release of 5-HT. Furthermore, it was found that substance P (10 M) stimulated 3H-dopamine release from nigral slices in vitro and the dopaminergic agonist apomorphine (50 M) also stimulated 3H-5-HT release. Substance P may, therefore, activate nigral dopaminergic neurones which then release dopamine from their dendrites. The release of dopamine may in turn stimulate 5-HT release from terminals of the raphe-nigral pathway. |
| |
Keywords: | Substantia nigra 5-Hydroxytryptamine -Flupenthixol" target="_blank">gif" alt="agr" align="BASELINE" BORDER="0">-Flupenthixol Substance P Dopamine |
本文献已被 SpringerLink 等数据库收录! |
|