عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Nitric oxide synthase has been detected in dorsal hippocampus, which is a key brain region that seems mediate behavioral effect of ethanol and nicotine. In the present study, the effects of L-arginine, a nitric oxide precursor, in the dorsal hippocampus in nicotineandrsquo;s effect on ethanol-induced amnesia was investigated.This experimental study was performed on 300 male mice. Mice were anesthetized with intra-peritoneal injection of ketamine hydrochloride, plus xylazine and then placed in a stereotaxic apparatus. The animals were bilaterally implanted with chronic cannulae in the CA1 regions of the dorsal hippocampus, trained in a step-down type inhibitory avoidance task, and tested 24 h after training to measure step-down latency. Pre-training or pre-test injection of ethanol (1 g/kg) decreased the memory retrieval. Injection of nicotine or L-arginine before test by itself has no effect on memory retrieval. On the other hand, pre-test administration of ethanol (0.5, 1 g/kg), nicotine (0.4, 0.8 andmicro;g/mice) or L-arginine (0.8 andmicro;g/mice) plus non-effective dose of nicotine (0.2 andmicro;g/mice) restored memory impairment induced by pre-training injection of ethanol. These results suggest that nitric oxide system of dorsal hippocampus may play an important role in the improving effect of nicotine on the ethanol-induced amnesia.