Effect of an angiotensin converting enzyme inhibitor (SQ 14,225) on beta-adrenergic and angiotensin-induced thirsts.
The effect of acute administration of SQ 14,225, a new angiotensin converting enzyme inhibitor, on the drinking response of female rats administered either isoprenaline, angiotensin I, or angiotensin II was studied during 2 h after treatment. Administration of isoprenaline (25 micrograms/kg body wt) was accompanied by a significant increase in water intake when compared with saline-treated controls. Acute administration of a constant dose of isoprenaline (25 micrograms/kg body wt) and increasing doses of SQ 14,225 (5--50 mg/kg) was accompanied by a dose-related, linear decrease in water intake. Acute administration of either angiotensin I or angiotensin II (200 micrograms/kg body wt) was accompanied by a significant increase in water intake. The dipsogenic response to angiotensin II was not affected by acute administration of 35 mg SQ 14,225/kg body wt. However, at the same dose of SQ 14,225, angiotensin I-induced thirst was attenuated. Since isoprenaline-induced and angiotensin I-induced, but not angiotensin II-induced, thirsts are blocked by SQ 14,225, the results suggest that isoprenaline-induced thirst is mediated by way of the renin--angiotensin system.
D000803:Angiotensin I / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000806:Angiotensin-Converting Enzyme Inhibitors; D000818:Animals; D004326:Drinking / Q000187:drug effects; D005260:Female; D007545:Isoproterenol / Q000494:pharmacology; D011392:Proline / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D013894:Thirst / Q000187:drug effects*
D000806:Angiotensin-Converting Enzyme Inhibitors; D000804:Angiotensin II; D000803:Angiotensin I; D011392:Proline; D007545:Isoproterenol