Angiotensin-related sodium appetite and thirst in cattle

Abstract

Cows depleted of Na by loss of saliva from a parotid fistula for 46 h had an avid appetite for Na solution. They drank 21.0 ± 1.6 liter of 0.3 M NaHCO3-NaCl solution during 2 h of access but little or no water during that time. Solutions of angiotensin II or captopril were infused for 3 h intravenously or into a lateral ventricle (intracerebroventricular) beginning 1 h before access to Na solution. Intravenous angiotensin II increased Na intake (to 26.8 ± 2.9 liter, P < 0.01) but did not alter water intake. Intracerebroventricular angiotensin II increased water intake but did not alter Na intake. Intravenous captopril reduced Na intake (to 11.0 ± 2.1 liter, P < 0.001) and concurrent intraven..