Drinking in the rhesus monkey: peripheral factors.

Rhesus monkeys prepared with chronic cannulae implanted in the stomach and duodenum were water deprived for 22.5 hr. With both cannulae closed, a mean of 137 ml was drunk within a 60-min period. When ingested water drained freely from an open gastric cannula, continuous drinking far in excess (878 ml mean intake) of normal occurred. Sham drinking also exceeded (634 ml mean intake) normal when ingested water drained through an open duodenal cannula. This pattern of continuous sham drinking indicates that oropharyngeal stimulation is not sufficient alone, or together with the passage of water through the stomach and the initial part of the duodenum, to terminate drinking. Duodenal infusions of water (25-100 ml) slowed or stopped gastric sham drinking in a dose-dependent fashion, but equivalent infusions of isotonic saline were without effect. Thus, pre- or postabsorptive signals at or beyond the level of the intestine distal to the site of the duodenal cannula are probably important for the termination of drinking in the rhesus monkey.