Rapid effect of change in cerebrospinal fluid sodium concentration on salt appetite [12]

Abstract

THIRST can be evoked within 1-2 min by intracarotid infusion of hypertonic NaCl. In contrast, the onset of a specific appetite for sodium salts as a result of rapid loss of body sodium is slow. A parotid fistula in naive sheep can produce a significant Na deficit (200-700 mmol) within 1-3 d but a Na appetite usually develops after 2-5 d (ref. 1). With large urinary water and Na loss induced by frusemide, water intake occurs within an hour but Na appetite is delayed until 24 h (ref. 2). Moreover, in the Na-depleted sheep or goats, increase in the Na concentration of cerebral arterial blood by 10-30 mmol l-1 by slow intracarotid infusion of 4 M NaCl for 7 min before or during presentation of N..