Intracerebroventricular administration of histamine in conscious mice induces catalepsy

. Histamine (10-80 'g), when injected intracerebroventricularly in conscious mice, was found to induce dose dependent degree of catalepsy. Histamine-induced catalepsy was antagonised by chlorcyclizine, a H1-receptor blocker, while pretreatment with metiamide, a H2-receptor blocker, had no effect on histamine-induced catalepsy. The results indicate that the cataleptic effect of histamine is mediated through activation of H1 receptors.