title: Involvement of dopamine receptor subtypes in dopaminergic modulation of aldosterone secretion in rats.
abstract: The postulation that dopamine (DA) may tonically inhibit aldosterone (ALDO) secretion has arisen from the finding that metoclopramide, a non-selective DA receptor antagonist with prominent non-dopaminergic actions, stimulates ALDO secretion. Experiments were performed to determine: (a.) the ability of several non-specific and subtype-specific DA receptor antagonists to stimulate ALDO secretion, (b.) the subtype DA receptor involved in regulating ALDO secretion, and (c.) if ALDO responses were associated with changes in plasma Na+(pNa), K+(pK), or osmolality (pOsm). Blood samples were withdrawn from carotid arterial catheters in conscious, fasted male Sprague-Dawley rats before and following intra-arterial administration of lactated Ringer's placebo, furosemide (10 mg/kg), or one of several DA receptor antagonists. Furosemide stimulated ALDO, decreased pK, and left pNa and pOsm unchanged. The non-selective DA receptor antagonists metoclopramide (0.2, 0.6 mg/kg), rs-sulpiride (0.2 mg/kg), and haloperidol (0.1 mg/kg), and the DA-2 receptor antagonists domperidone (0.1 mg/kg) and s-sulpiride (0.1 mg/kg) each stimulated ALDO, and left pNa, pK, and pOsm unchanged. Conversely, the DA-1 receptor antagonists SCH 23390 (0.03, 0.1 mg/kg) and r-sulpiride (0.1 mg/kg) failed to stimulate ALDO, and left pNa, pK, and pOsm unaltered. These studies suggest that ALDO secretion in rats is modulated by a mechanism involving DA-2, but not DA-1 subtype receptors, and that the ALDO responses to DA receptor antagonism are independent of changes in pNa, pK, and pOsm.
mesh_terms: D000450:Aldosterone / Q000378:metabolism*; D000818:Animals; D001769:Blood; D004294:Domperidone / Q000494:pharmacology; D004298:Dopamine / Q000502:physiology*; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D008787:Metoclopramide / Q000494:pharmacology; D009994:Osmolar Concentration; D011188:Potassium / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000502:physiology*; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D012964:Sodium / Q000097:blood; D013469:Sulpiride / Q000494:pharmacology
chemical_list: D011954:Receptors, Dopamine; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D000450:Aldosterone; D004294:Domperidone; D013469:Sulpiride; D012964:Sodium; D006220:Haloperidol; D008787:Metoclopramide; D011188:Potassium; D004298:Dopamine