Effects of brain histamine on memory deficit induced by nucleus basalis-lesion in rats.

Aim: To investigate whether or not brain histamine was involved in memory deficits induced by lesions of nucleus basalis magnocellularis (NBM) in rats.

Methods: Passive avoidance response was used to measure memory process in rats, and NBM was bilaterally lesioned by injection of ibotenic acid (6 microg/site).

Results: Icv injection of histamine (500 ng), and ip injection of histidine (1500 mg/kg), metoprine (10 mg/kg) or tacrine (3, 5 mg/kg) ameliorated memory impairment induced by NBM lesion regarding passive avoidance response. The ameliorating effect of histidine was antagonized by pyrilamine (2-5 mg/kg), a H1-antagonist, but not by zolantidine, a H2-antagonist.

Conclusion: Histaminergic neurons play an important role in learning and memory via H1-receptor, and its action may be due to cholinergic neurons.