Rowland N E, Del Bianco A, Fregly M J
Department of Psychology, University of Florida, Gainesville 32611-2250, USA.
Regul Pept. 1996 Oct 22;66(3):163-7. doi: 10.1016/S0167-0115(96)00095-X.
Water intake was examined in young (3-5 months) and old (20-24 months) rats following peripheral administration of either angiotensin (Ang) II or captopril+bradykinin (BK). Relative to body weight, intake after Ang II showed no age-related difference, while that after captopril+BK was markedly reduced in the old rats. In other rats that were not allowed to drink after captopril+BK, the induction of Fos-like immunoreactivity (IR) was much lower in the subfornical organ, supraoptic and median preoptic nuclei of old rats compared with their young counterparts. Intake of 0.15 M NaCl during chronic dietary administration of enalapril was robust in young rats but was much reduced in old rats, as was their plasma renin activity. Thus, reduced thirst and sodium appetite are found in conjunction with kininase II (angiotensin-converting enzyme) inhibitors in aging rats, possibly because they fail to generate the high levels of circulating renin seen in young rats under these conditions.
