Sensory mechanisms in the behavioral control of body fluid balance: thirst and salt appetite.

The review focuses on the mechanisms of action and interaction of afferent signaling pathways involved in the mediation of the behavioral responses to thirst and sodium appetite. Water volume in intracellular and extracellular body fluid compartments, experimental manipulation of cellular and extracellular, and autonomic and endocrine responses to hypovolemia are explained. The roles of the renal renin-angiotensin system in behavioral control of fluid balance and of angiotensin II in isoproterenol-induced drinking are explored. Studies in dogs provide a basis for understanding hypotension and angiotensin II-induced drinking. The functions of hypovolemia, hypotension, and the renin-angiotensin system in the control of sodium appetite are examined.