Zolpidem involvement on memory and hypnotic effect of ethanol in chronically ethanol-treated rats

Multiple (10x) treatment of zolpidem (1.0 or 2.0 mg/kg, orally, p.o.) led t o different effects in chronically ethanol-treated and control rats. In con trol rats, after repeated zolpidem administration, a weaker, when compared to single administration, hypnotic effect of ethanol was observed, which ma y be the result of tolerance developed towards the inhibitory effect of zol pidem. However, in chronically ethanol-treated rats, the multiple zolpidem treatment led to prolongation of ethanol-induced sleep similar to the value s observed in non-zolpidem-treated control animals. This suggests that zolp idem multiple administration may inhibit tolerance towards ethanol in chron ically ethanol-treated rats. In the experiment with zolpidem, there were ef fects on performance in a memory test and the impairment of passive avoidan ce task after multiple drug treatment when compared to the effects after si ngle administration in control rats. In contrast, in chronically ethanol-tr eated rats, amplification of latency (especially after 2.0 mg/kg) was obser ved. The possible relationship between ethanol-induced sedation and latency values would be consistent with a higher contribution of the inhibitory ef fect of zolpidem, than a direct influence on memory processes in chronicall y ethanol-treated rats.