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Query: UMLS:C0004135 (ATM)
 13,001 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Because dopamine influences arginine vasopressin (AVP) release, the present studies were designed to ascertain the dopamine receptor subtype that potentiates angiotensin II-induced AVP secretion in cultured hypothalamo-neurohypophysial explants. Dopamine (a nonselective D1/D2 agonist), apomorphine (a D2 >> D1 agonist), and SKF-38393 (a selective D1 agonist) dose dependently increased AVP secretion. Maximal AVP release was observed with 5 microM dopamine, 307 +/- 66% . explant-1 . h-1, 1 microM SKF-38393, 369 +/- 41% . explant-1 . h-1, and 0.1 microM apomorphine, 374 +/- 67% . explant-1 . h-1. Selective D1 antagonism with 1 microM SCH-23390 blocked AVP secretion to values no different from basal. Domperidone (D2 antagonist), phenoxybenzamine (nonselective adrenergic antagonist), and prazosin (alpha1-antagonist) failed to prevent release. D1 antagonism also prevented AVP secretion to 1 microM angiotensin II [angiotensin II, 422 +/- 87% . explant-1 . h-1 vs. angiotensin II plus SCH-23390, 169 +/- 28% . explant-1 . h-1 (P < 0.05)], but D2 and alpha1-adrenergic blockade did not. In contrast, AT1 receptor inhibition with 0.5 microM losartan blocked angiotensin II- but not dopamine-induced AVP release. AT2 antagonism had no effect. Although subthreshold doses of the agonists did not increase AVP secretion (0. 05 microM dopamine, 133 +/- 44% . explant-1 . h-1; 0.01 microM SKF-38393, 116 +/- 26% . explant-1 . h-1;and 0.001 microM angiotensin II, 104 +/- 29% . explant-1 . h-1 ), the combination of dopamine and angiotensin II provoked a significant rise in AVP [420 +/- 83% . explant-1 . h-1 (P < 0.01)]. Similar results were observed with SKF-38393 and angiotensin II, and the AVP response was blocked to basal levels by either D1 or AT1 antagonism. These findings support a role for D1 receptor activation to increase AVP release and mediate angiotensin II-induced AVP release within the hypothalamo-neurohypophysial system. The data also suggest that the combined subthreshold stimulation of receptors that use distinct intracellular pathways can prompt substantial AVP release.
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PMID:Dopaminergic control of angiotensin II-induced vasopressin secretion in vitro. 975 89