Cross-talk between M2 muscarinic and D1 dopamine receptors in the cat adrenal medulla.
In the study reported here we have reached two conclusions. First, the cat adrenal medulla chromaffin cell possesses a dopamine D1 receptor that seems to be coupled to an adenylyl cyclase. Second, this receptor regulates the muscarinic-mediated catecholamine release response through a negative feed-back loop which uses cyclic AMP as a second messenger. These conclusions are supported by the following findings: (i) SKF38393 (a selective D1 receptor agonist), but not quinpirole (a selective D2 agonist), inhibits the methacholine-mediated catecholamine release responses in a concentration-dependent manner (IC50 of around 1-2 microM). (ii) SCH23390 (a selective D1 antagonist), but not sulpiride (a selective D2 antagonist), reversed by 70% the inhibitory effects of SKF38393. (iii) Dibutyril cyclic AMP (500 microM) inhibited by 80% the secretory effects of methacholine.
Departamento de Farmacología, Facultad de Medicina, Universidad Autónoma de Madrid, Spain.
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Albillos
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Abad
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García
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000262:Adenylyl Cyclases / Q000378:metabolism; D000313:Adrenal Medulla / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology; D002415:Cats; D015259:Dopamine Agents / Q000494:pharmacology*; D004873:Ergolines / Q000494:pharmacology; D016210:Methacholine Chloride / Q000494:pharmacology; D019257:Quinpirole; D011954:Receptors, Dopamine / Q000187:drug effects / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism*; D015290:Second Messenger Systems; D013469:Sulpiride / Q000494:pharmacology
D001552:Benzazepines; D015259:Dopamine Agents; D004873:Ergolines; D011954:Receptors, Dopamine; D011976:Receptors, Muscarinic; D016210:Methacholine Chloride; D019257:Quinpirole; D003994:Bucladesine; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D013469:Sulpiride; D000262:Adenylyl Cyclases