Feeding, drinking, and temperature responses of chickens to intracerebroventricular histamine

The present study examines the effects of intracerebroventricular injections of histamine (HA) and two HA antagonists, the H(1) receptor antagonist chloropheneramine maleate (CM) and the H(2) receptor antagonist cimetidine (CIM), on food and water consumption and body temperature in chickens. Single-Comb White Leghorns (SCWL) and broiler cockerels were utilized for these experiments. The first pair of experiments consisted of intracerebroventricular injections of HA and its effects on food and water consumption. HA was infused at dosages of 0, 25, 50, and 100 microg/10 microl of artificial cerebrospinal fluid (aCSF). HA significantly decreased food and water intake in a dose-dependent manner. The second pair of experiments examined the effects of HA on water intake while birds had no access to feed. Water intake was not significantly affected by intracerebroventricular injections of HA. The next pair of experiments examined the effects of HA on body temperature. In SCWL, body temperature was not affected by HA until 165 min postinjection when HA decreased temperature in a quadratic dose-response with maximum hypothermia being achieved at a dose of 25 microg. In contrast, HA increased body temperature in broilers beginning at 75 min postinjection. In the final series of experiments, the anorexia induced by HA was attenuated in SCWL and broilers with pretreatment of either CM or CIM. These results suggest that HA has an anorexigenic effect in SCWL and broiler cockerels, and this effect is mediated by both H(1) and H(2) receptors. Water intake is not directly affected by the intracerebroventricular injection of HA. Whereas HA increased body temperature in broilers, the response in SCWL is equivocal.