The role of central endogenous histamine and H1, H2 and 8 3 receptors on food intake in broiler chickens

The role of endogenous histamine and H), H2 and H) central receptors on food intake in broiler chickens was investigated. For this purpose, a probe was used to manipulate the concentration of endogenous histamine by intracerebroventricular (ICV) injection of thioperamide, an H3 receptor antagonist, and R-amethylhistamine, an H3 receptor agonist and subsequently the effects of brain histaminergic system on food intake was assessed. Moreover, to determine the receptors involved in histamine-induced feeding behaviour changes, HI and H2 blockers were administered to thioperamide-treated chickens. Injection of thioperamide (600 and 300 nmol) decreased food intake dose-dependently (P 0.05). On the contrary, ICV injection of R-amethylhistamine (400 and 200 nmol) increased food intake (P O.05). Chlorpheniramine (128 and 256 nmol), a HI receptor antagonist, increased food intake (P 0.05). Famotidine, a H2 receptor antagonist at 74 or 148 nmol had no effect on food intake but at 296 nmol significantly decreased food intake (P 0.05). Pretreatment with chlorpheniramine (256 nmol) significantly attenuated thioperamide effects (600 nmol) on food intake (P O.05). In conclusion, the results of the present study demonstrated that histamine exerts anorexigenic effects through HI but not H2 receptors in broiler chickens. Furthermore, it was shown that thioperamide through stimulation of synthesis and release of endogenous neuronal histamine can decrease food intake in broiler chickens.