ANTAGONISM OF THE RENIN-ANGIOTENSIN SYSTEM AND WATER DEPRIVATION-INDUCED NACL INTAKE IN RATS

Adult male rats (n = 5-7 per group) were water deprived for 24 h with only food available. Then they had access to water for 2 h. At the end of the 2 h, 1.5% NaCl was offered to the animals and the intake was m easured for another 2 h. The rats drank an average of 9.8 +/- 3.0 ml/1 20 min of 1.5% NaCl; water intake during this time was negligible (not more than 1.0 ml/120 min). Captopril injected IP at the doses of 12 a nd 24 mg/kg induced 60-90% inhibition of the intake. Losartan or PD123 319 injected ICV induced 50-80% inhibition of the intake. Losartan (80 nmol) inhibited the intake at a lower dose than PD123319 (160 nmol). Neither losartan nor PD123319 inhibited 10% sucrose intake. The inhibi tion of 1.5% NaCl intake was not related to alterations in arterial pr essure. The results show that the antagonism of the renin-angiotensin system inhibits the 1.5% NaCl intake induced by water deprivation. The inhibition induced by the angiotensin II antagonists suggest that thi s peptide is important for the control of salt intake induced by water deprivation.