Effect of H1-antagonists on spatial memory deficit evaluated by 8-arm radial maze in rats.
OBJECTIVE
To evaluate effects of certain H1-antagonists on spatial memory with 8-arm radial maze performance of rats.


METHODS
Eight-arm radial maze performance was used to measure spatial memory in rats.


RESULTS
Chronic treatments of classical H1-antagonists, diphenhydramine (5 mg/kg) and pyrilamine (20 mg/kg) impaired acquisition memory process regarding both parameters of radial maze performance. In addition, the memory retrieval process was also impaired significantly by a single administration of diphenhydramine (5, 10 mg/kg) and pyrilamine (50 mg/kg). However, the newly developed H1-antagonist, epinastine caused no appreciable effect on both acquisition and retrieval memory even at a high dose of 50 mg/kg. The memory deficit induced by diphenhydramine (10 mg/kg) or pyrilamine (50 mg/kg) was reversed by tacrine (1 mg/kg).


CONCLUSIONS
Histamine H(1)-receptors plays a certain role in spatial cognition, and its action may be due to both histaminergic and cholinergic neurons.
Chen
Z
Z
Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou 310031, China. chenzfl@hotmail.com
Chen
J Q
JQ
Kamei
C
C
D000818:Animals; D003071:Cognition / Q000187:drug effects; D003984:Dibenzazepines / Q000494:pharmacology*; D004155:Diphenhydramine / Q000494:pharmacology*; D006634:Histamine H1 Antagonists / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008568:Memory / Q000187:drug effects; D008569:Memory Disorders / Q000139:chemically induced / Q000503:physiopathology*; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013619:Tacrine / Q000494:pharmacology
D003984:Dibenzazepines; D006634:Histamine H1 Antagonists; D007093:Imidazoles; D013619:Tacrine; D004155:Diphenhydramine; D011738:Pyrilamine; C053090:epinastine