The effects of histamine and its related compounds on impairment of the passive avoidance response induced by hippocampal lesions were studied in rats. A remarkable impairment of passive avoidance response was observed by bilateral dorsal hippocampal lesions. Intracerebroventricular injection of histamine and intraperitoneal injection of histidine improved the impairment of passive avoidance response in hippocampus-lesioned rats. An ameliorating effect of histamine on memory impairment was mediated via H1-receptors. H1- agonists, 2-thiazolylethylamine and 2-pyridylethylamine, caused the same effect as histamine, whereas H2-agonists, 4-methylhistamine and dimaprit, failed to improve the impairment of passive avoidance response. Pretreatment with H1-antagonists, diphenhydramine and chlorpheniramine, abolished the ameliorating effect of histamine on memory impairment, but H2-antagonists, cimetidine and ranitidine, caused no obvious effect. H3-antagonists, thioperamide and clobenpropit, also improved the memory impairment same as histamine. This effect was blocked by H3-agonist, (R)-α-methylhistamine and H1-antagonist, diphenhydramine, but not by H2-antagonist, cimetidine. Based on these findings, histamine improves the impairment of passive avoidance response induced by hippocampal lesions via H1-receptor. Presynaptic H3- receptor is also involved in modulation of the memory paradigm.
|Number of pages||16|
|Journal||Journal of Brain Science|
|Publication status||Published - 1997|
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