Objective: To elucidate the central role of histamine and its H1 and H2 receptors in the regulation of feeding behavior of rabbits. Design: Experimental study.
Animals: Thirty-six male New Zeland white rabbits weighing 2.5-3 kg.
Procedure: A 23-guage stainless steel guide cannula was implanted into the lateral ventricle of brain and intracerebroventricular injections of saline normal (control), histamine (75 mg). chlorpheniramina (H1) antagonist, 150 mg) and cimetidine (H2 antagoists,150 mg) through guide cannula with a 25-mi Hamilton syringe, were done respectively. Recording of feeding behavior was made in first meal including:
latency time to feeding, numbers and duration of consuming pellets, eating speed and measure of food intake at fixed post- injection intervals.
Statistical analysis: Repeated measures one-way ANOVA, and Duncan’s multiple range test.
Results: Latency time to feeding increased and decreased by histamine and chlorpheniramine, respectively. Pretreatment with chlorpheniramine but not cimetidine inhibited the histamine effect. Numbers and duration of consumed pellets decreased by histamine and increased by chlorpheniramine. There isnd any significant changes in eating speed. Injection of histamine decreased food intake in first and second hours. and chlorpheniramine but not cimetidine increased lh post- injection food intake. Histamine decreased 4h cumulative food intake, but the both antihistamine had no effect. Histamine and antihistamines had no effect. Histamine and antihistamines had no effects on total 24h food intake.
Clinical implication: From the results of this study it is concluded that brain histamine has a central suppressive role in feeding behavior which is mediated by its central H2 but not h2 receptors. In treatment of some anorexic states, the use of blood- brain penetrating Hi antihistamines could be recommended. J. Fac. Vet. Med. Univ. Tehran. 57, 1: 13-18, 2002.
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