role of central endogenous histamine and H[1], H[2] and H[3] receptors on food intake in broiler chickens

ABSTRACT

The role of endogenous histamine and H[1], H[2] and H[3] 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 H[3] receptor antagonist, and R-alpha-methylhistamine, an H[3] 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, H[1], 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-alphamethylhistamine [400 and 200 nmol] increased food intake [P<0.05]. Chlorpheniramine [128 and 256 nmol], a H[1] receptor antagonist, increased food intake [P<0.05]. Famotidine, a H[2] 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<0.05]. In conclusion, the results of the present study demonstrated that histamine exerts anorexigenic effects through H[1], but not H[2] 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