Facilitating effects of histamine on spatial memory deficit induced by scopolamine in rats.
OBJECTIVE
To investigate whether or not histamine was involved in scopolamine-induced spatial memory deficits evaluated in 8-arm radial maze performance of rats.


METHODS
Eight-Arm radial maze performance was used to measure spatial memory in rats, and the brain regions were subsequently dissected and histamine contents were determined by HPLC.


RESULTS
Intracerebroventricular (icv) injection of histamine (100 or 200 ng) or thioperamide (50 micrograms), and intraperitoneal (i.p.) injection of histidine (1000 mg/kg) ameliorated memory impairment induced by scopolamine regarding both parameters of radial maze performance. 2-Thiazolylethylamine, but not 4-methylhistamine showed the similar effect to histamine. Both histamine (200 ng, icv) and histidine (1000 mg/kg, i.p.) were equally effective in increasing the histamine content in the cortex, hippocampus, and hypothalamus.


CONCLUSIONS
These results suggest that brain histamine plays an important role in learning and memory, and its action may be due to cholinergic neurons.
Chen
Z
Z
Department of Pharmacology, Basic Medical College, Zhejiang University, Hangzhou 310031, China. chenzfl@hotmail.com
Kamei
C
C
D000818:Animals; D001921:Brain / Q000378:metabolism*; D006632:Histamine / Q000494:pharmacology*; D017442:Histamine Agonists / Q000494:pharmacology; D006633:Histamine Antagonists / Q000494:pharmacology; D006639:Histidine / Q000494:pharmacology; D007276:Injections, Intraventricular; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008569:Memory Disorders / Q000139:chemically induced / Q000378:metabolism*; D010880:Piperidines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012601:Scopolamine; D013844:Thiazoles / Q000494:pharmacology
D017442:Histamine Agonists; D006633:Histamine Antagonists; D010880:Piperidines; D013844:Thiazoles; C029345:2-(2-aminoethyl)thiazole; D006639:Histidine; D006632:Histamine; D012601:Scopolamine; C052075:thioperamide