Histamine ameliorates spatial memory deficits induced by MK-801 infusion into ventral hippocampus as evaluated by radial maze task in rats.
OBJECTIVE
To investigate the role of histamine in memory deficits induced by MK-801 infusion into the ventral hippocampus in rats.


METHODS
An 8-arm radial maze (4 arms baited) was used to assess spatial memory.


RESULTS
Bilateral ventral intrahippocampal (ih) infusion of MK-801 (0.3 microg/site), an N-methyl-D-aspartate (NMDA) antagonist, impaired the retrieval process in both working memory and reference memory. Intrahippocampal injection of histamine (25 or 50 ng/site) or intraperitoneal (ip) injection of histidine (25, 50 or 100 mg/kg) markedly ameliorated the spatial memory deficits induced by MK-801. Both the histamine H1 antagonist pyrilamine (0.5 or 1.0 microg/site, ih) and the H2 antagonist cimetidine (2.5 microg/site, ih) abolished the ameliorating effect of histidine (100 mg/kg, ip) on reference memory deficits, but not that on working memory deficits induced by MK-801.


CONCLUSIONS
The results indicate that histamine in the ventral hippocampus can ameliorate MK-801-induced spatial memory deficits, and that histamine's effect on reference memory is mediated by postsynaptic histamine H1 and H2 receptors.
Xu
Li-Sha
LS
Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou 310031, China.
Yang
Li-Xia
LX
Hu
Wei-Wei
WW
Yu
Xiao
X
Ma
Li
L
Liu
Lu-Ying
LY
Wei
Er-Qing
EQ
Chen
Zhong
Z
D000818:Animals; D002927:Cimetidine / Q000494:pharmacology; D016291:Dizocilpine Maleate; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000187:drug effects / Q000503:physiopathology*; D006632:Histamine / Q000008:administration & dosage / Q000494:pharmacology*; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D006639:Histidine / Q000008:administration & dosage / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008569:Memory Disorders / Q000139:chemically induced / Q000503:physiopathology*; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley
D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D006639:Histidine; D016291:Dizocilpine Maleate; D002927:Cimetidine; D006632:Histamine; D011738:Pyrilamine