?-Opioid Receptors and Not K-Opioid Receptors Are Coupled to the Adenylate Cyclase in the Cerebellum
| Autor: | J.-P. Thouvenot, Ph. Jauzac, M.-J. Boyer, Y. Quertermont, Jean-Claude Meunier, J. Polastron |
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| Rok vydání: | 1990 |
| Předmět: |
Narcotics
medicine.medical_specialty Guinea Pigs Receptors Opioid mu Adenylate kinase Biology Pertussis toxin Biochemistry Cyclase Cellular and Molecular Neuroscience Cerebellum Internal medicine medicine Animals Virulence Factors Bordetella Receptor Membranes Receptors Opioid kappa Colforsin Endocrinology Pertussis Toxin Etorphine Opioid ADP-ribosylation Adenylyl Cyclase Inhibitors Receptors Opioid Adenylate Cyclase Toxin Rabbits Cyclase activity Adenylyl Cyclases medicine.drug |
| Zdroj: | Journal of Neurochemistry. 54:562-570 |
| ISSN: | 1471-4159 0022-3042 |
| Popis: | The putative regulatory effect of opioids on adenylate cyclase was investigated in two different preparations containing, respectively, two different populations of opioid receptors: the rabbit cerebellum (greater than 75% mu-opioid receptors) and the guinea pig cerebellum (greater than 80% kappa-opioid receptors). In the mu-preparation, but not in the kappa-preparation, opioids inhibited the basal and the forskolin-stimulated adenylate cyclase activity in a dose-dependent manner and stereospecifically. The inhibition was in the 20-30% range, required the presence in the assay medium of Mg2+ and of GTP, but was independent of the presence of Na+. Pharmacological characterization of the inhibitory response in the rabbit cerebellum clearly showed that it was under the control of a mu-opioid binding site, with the effect being elicited by non-selective (etorphine and morphine) and mu-selective (Tyr-D-Ala-Gly-Me-Phe-Gly-ol) agonists, whereas delta- and kappa-selective agonists were almost totally ineffective. ADP ribosylation of inhibitory GTP-binding protein by pertussis toxin failed to block the inhibitory effect of opioids, and data presented suggest that this failure is likely to be the consequence of a limited access of the toxin to its substrate in rabbit cerebellum membranes. |
| Databáze: | OpenAIRE |
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