Inhibition of sham feeding by hyperosmotic gastric infusions in rat

In rats with esophagestomy and gastric cannulas, oral and postingestive events that accom- pany feeding can be varied independently. In food-deprived but not water-deprived rats, infusion of hypertonic NaCl concurrent with glucose sham feeding rapidly inhibited feeding, relative to isotonic NaCl, and was about as effective as i.g. glucose itself in bringing the ingestive bout to an end. This equivalence held over a range of glucose concentrations, or a complex liquid diet, when these were offered for oral ingestion. The inhibition was not accompanied by responsive- ness to water. These findings extend earlier ones with water-deprived rats and show that osmotic factors can inhibit feeding without evoking thirst.