title: Effects of histamine H(1) receptor antagonists on hippocampal theta rhythm during spatial memory performance in rats.
abstract: The effects of histamine H(1) receptor antagonists (promethazine, diphenhydramine, chlorphenilamine and triprolidine) on hippocampal theta rhythm during eight-arm radial maze performance were investigated using rats. Promethazine showed a significant increase in the number of total errors and working memory errors at doses of 10 and 20 mg/kg, and a significant increase was also observed in reference memory errors at a dose of 20 mg/kg. Diphenhydramine and chlorphenilamine at a dose of 20 mg/kg and triprolidine at a dose of 35 mg/kg also caused significant increases in the number of total, reference memory and working memory errors. Promethazine, diphenhydramine and chlorphenilamine, having potent anti-muscarinic receptor properties, increased hippocampal theta power during radial maze performance at a dose of 20 mg/kg. On the other hand, triprolidine, which has weak anti-muscarinic receptor properties compared with other histamine H(1) receptor antagonists, decreased theta power at a dose of 35 mg/kg. These results suggest that anti-muscarinic receptor properties rather than anti-histamine H(1) receptor properties may affect hippocampal theta power during spatial memory deficit induced by promethazine, diphenhydramine and chlorphenilamine.
authors: Department of Medicinal Pharmacology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8530, Japan.
authors: Takayoshi
authors: T
authors: Masuoka
authors: Azusa
authors: A
authors: Mikami
authors: Masa
authors: M
authors: Yasuda
authors: Kazuaki
authors: K
authors: Shinomiya
authors: Chiaki
authors: C
authors: Kamei
mesh_terms: D000818:Animals; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D006634:Histamine H1 Antagonists / Q000494:pharmacology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008569:Memory Disorders / Q000139:chemically induced* / Q000503:physiopathology; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013826:Theta Rhythm / Q000187:drug effects
chemical_list: D006634:Histamine H1 Antagonists