Induction of food intake by a GABAergic mechanism in the turkey.

The effect of GABAergic influences on food and water intake in Large White turkeys was investigated. In Experiment 1, food and water intake were monitored in hens injected intracerebroventricularly (ICV) with varying doses of muscimol, a GABA agonist. In Experiment 2, hens were pretreated with ICV injections of picrotoxin, a GABA antagonist, prior to the injection of muscimol. In Experiment 3, the effect of ICV injections of muscimol on water intake was determined in hens not allowed access to food. The ICV injection of muscimol caused a dose-dependent increase in food intake with 75 nmole being the most efficacious dose. Water intake was stimulated following the injection of muscimol when food and water were available ad lib. However, water intake was not affected by the ICV injection of muscimol if food was not simultaneously available, indicating that the increased water intake was a result of increased food intake. The effect of muscimol on food intake was significantly attenuated by pretreatment with picrotoxin. It appears, therefore, that GABA acts within the brain of the turkey to increase food, but not water, intake.