Angiotensin and Na appetite of sheep.
The effect of both intravenous (iv; 24 micrograms/h) and intracerebroventricular (ivt; 3.8 micrograms/h) infusion over 1-2 days of angiotensin II (ANG II) on Na intake of both Na-replete and -deplete sheep (i.e., 22 h loss of parotid saliva) was observed. In Na-replete sheep with continuous access to water and 2-h daily access to 0.5 M NaCl solution, both iv and ivt ANG II caused an increase in Na intake. The increase in Na intake caused by iv or ivt ANG II was preceded by a Na deficit due to increased urinary Na excretion. The increase in Na intake was eliminated by the continuous return of urine. In Na-deplete sheep with continuous access to water and 2-h daily access to 0.6 M NaHCO3 solution, iv ANG II caused no change in Na loss but a small increase in Na intake during the 1st day of infusion. The ivt ANG II caused no change in Na loss or in Na intake. The iv ANG II caused a small and inconsistent increase in water intake in Na-replete sheep but did not cause any change in water intake of Na-deplete sheep. The ivt ANG II caused a large increase in water intake in both Na-replete and -deplete sheep. In both Na-replete and -deplete sheep, iv ANG II did not alter cerebrospinal fluid or plasma [Na] or osmolality but decreased plasma [K]. The ivt ANG II decreased both cerebrospinal fluid and plasma [Na] and osmolality. The results of the present experiments are consistent with the proposition that the ANG II-induced Na appetite in sheep is largely due to an ANG II-induced Na loss preceding the development of appetite.
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001066:Appetite / Q000187:drug effects*; D002552:Cerebral Ventricles / Q000502:physiology; D004326:Drinking / Q000187:drug effects; D004435:Eating / Q000187:drug effects; D005260:Female; D007262:Infusions, Intravenous; D007276:Injections, Intraventricular; D011188:Potassium / Q000097:blood / Q000134:cerebrospinal fluid; D012756:Sheep; D012964:Sodium / Q000097:blood / Q000134:cerebrospinal fluid
D000804:Angiotensin II; D012964:Sodium; D011188:Potassium