| Autor: |
Stirling JM; Astra Neuroscience Research Unit, London, U.K., Cross AJ, Robinson TN, Green AR |
| Jazyk: |
angličtina |
| Zdroj: |
Neuropharmacology [Neuropharmacology] 1989 Jul; Vol. 28 (7), pp. 699-704. |
| DOI: |
10.1016/0028-3908(89)90153-6 |
| Abstrakt: |
The effects of GABAB agonists and putative antagonists on intrasynaptosomal calcium ion concentrations ([Ca2+]i) after stimulation with potassium ions were studied with the fluorescent probe Quin 2. gamma-Aminobutyric acid and (-)-baclofen, but not (+)-baclofen, produced a dose-dependent inhibition of the potassium-stimulated [Ca2+]i in cortical synaptosomes from the rat. This effect was mimicked by another GABAB agonist SL75102 and weakly by muscimol. It was not inhibited by the alpha-adrenoceptor antagonist phentolamine. This system thus appears to provide a useful test of GABAB receptor function. None of the putative GABAB antagonists, phaclofen, delta-aminovaleric acid or beta-phenyl GABA inhibited responses to (-)-baclofen. Indeed, all three compounds produced similar responses to that seen with (-)-baclofen, suggesting that they act as agonists in this system. These data suggest that those GABAB receptors modulating [Ca2+]i have a distinct pharmacology from post-synaptic GABAB receptors, defined in electrophysiological experiments. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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