Preabsorptive pregastric vagally mediated histaminergic component of drinking elicited by eating in the rat

Preabsorptive stimulation by food was confined to the pregastric (oropharynx and esophagus) segment of the gastrointestinal tract by having male Sprague-Dawley rats sham feed liquid food which then drained out a gastric cannula. This procedure provided a paradigm for studying the effect of preabsorptive pregastric food-contingent stimulation on drinking behavior. Sham feeding elicited drinking that was (a) attenuated by complete bilateral subdiaphragmatic vagotomy (with hepatic branch intact), (b) attenuated by peripheral cholinergic blockade with intraperitoneal atropine methyl nitrate (0.25 mg/kg), and (c) abolished by combined antagonism of H1 and H2 histamine receptors with the use of intraperitoneal dexbrompheniramine (1 mg/kg) and cimetidine (16 mg/kg). These results provide evidence for a preabsorptive pregastric vagally mediated histaminergic component of drinking elicited by eating in the rat.