Effects of a novel arginine-vasopressin derivative, NC-1900, on the spatial memory impairment of rats with transient forebrain ischemia.
NC-1900, an arginine-vasopressin derivative, has been reported to enhance memory for avoidance behavior. Specifically, NC-1900 ameliorated cycloheximide-induced learning impairments in a passive avoidance test in rats. In the present study, we investigated that effects of NC-1900 on place learning in rats with selective lesions in the CA1 subfield of the hippocampal formation produced by transient forebrain ischemia. NC-1900 was administered daily (1 microg/kg, p.o.) 1 h before the place learning task. A rat was required to alternate between 2 small circular areas located diametrically opposite each other on the circumference of an open field in order to obtain intracranial electrical stimulation reward (the spatial navigation task). Rats with hippocampal lesions showed severe place learning impairments both in task performance (indicated by number of rewards obtained per a session) and in navigation performance (forming efficient trails) over the 30-day test period. Treatment with NC-1900 ameliorated deficits in the place learning exhibited by rats with the same hippocampal lesions, such that their performance reached normal levels. There were no significant differences in the ischemic hippocampal lesions, spontaneous locomotor activity, and stimulation current intensity between the treated and untreated rats. The results demonstrated that NC-1900 reduced place learning impairments produced by hippocampal lesions.
Hori
Etsuro
E
Department of Physiology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Sugitani 2630, Toyama 930-0194, Japan.
Uwano
Teruko
T
Tamura
Ryoi
R
Miyake
Norihisa
N
Nishijo
Hisao
H
Ono
Taketoshi
T
D000647:Amnesia / Q000188:drug therapy; D000818:Animals; D002545:Brain Ischemia / Q000150:complications*; D004195:Disease Models, Animal; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D007858:Learning / Q000187:drug effects / Q000502:physiology; D008297:Male; D008569:Memory Disorders / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D009842:Oligopeptides / Q000494:pharmacology* / Q000627:therapeutic use; D016548:Prosencephalon / Q000098:blood supply*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D051381:Rats; D017208:Rats, Wistar; D014667:Vasopressins / Q000494:pharmacology* / Q000627:therapeutic use
C115056:NC 1900; D009842:Oligopeptides; D014667:Vasopressins; D011761:Pyrrolidonecarboxylic Acid