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Central-type benzodiazepines and the octadecaneuropeptide modulate the effects of GABA on the release of α-melanocyte-stimulating hormone from frog neurointermediate lobe in vitro
| Content Provider | Semantic Scholar |
|---|---|
| Author | Tonon, M. C. Adjeroud, S. Lamacz, Marek Louiset, Estelle Vaudry, Hubert |
| Copyright Year | 1989 |
| Abstract | The involvement of the GABA-benzodiazepine receptor complex in the regulation of melanotropin secretion has been investigated using perfused frog neurointermediate lobes. The GABAA agonist 3-amino-1 propane sulfonic acid mimicked the biphasic effect of GABA on alpha-melanocyte-stimulating hormone secretion: a brief stimulation followed by an inhibition of melanotropin secretion. The GABAA antagonist SR 95531 (10(-4) M) inhibited both stimulation and inhibition of alpha-melanocyte-stimulating hormone release induced by GABA (10(-4) M). Since the inhibitory effect of baclofen (10(-4) M) was partially antagonized by SR 95531 (10(-4) M), it appears that the GABAergic control of alpha-melanocyte-stimulating hormone release is mainly achieved through activation of GABAA receptors. GABA-induced stimulation of alpha-melanocyte-stimulating hormone release was inhibited by tetrodotoxin (10(-5) M), an Na+ -channel blocker, or nifedipine (10(-5) M), a voltage-dependent Ca2+ -channel blocker, suggesting that Na+ and Ca2+ ions are involved in the stimulatory phase of GABA action. Only central-type benzodiazepine binding site agonists such as clonazepam (10(-4) M) modified alpha-melanocyte-stimulating hormone release. In fact, clonazepam (10(-7) to 10(-5) M) led to a dose-dependent potentiation of both GABA-induced stimulation and inhibition of alpha-melanocyte-stimulating hormone release. This potentiating effect was antagonized by the GABAA antagonist SR 95531 (10(-4) M) or by the central-type benzodiazepine binding site antagonist flumazenil (10(-4) M), whereas picrotoxin (10(-4) M) abolished only the stimulatory phase.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Starting Page | 485 |
| Ending Page | 493 |
| Page Count | 9 |
| File Format | PDF HTM / HTML |
| DOI | 10.1016/0306-4522(89)90391-6 |
| PubMed reference number | 2552350 |
| Journal | Medline |
| Volume Number | 31 |
| Alternate Webpage(s) | https://api.elsevier.com/content/article/pii/0306452289903916 |
| Alternate Webpage(s) | https://www.sciencedirect.com/science/article/pii/0306452289903916?dgcid=api_sd_search-api-endpoint |
| Alternate Webpage(s) | https://doi.org/10.1016/0306-4522%2889%2990391-6 |
| Journal | Neuroscience |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
