LEARNING AND TOLERANCE TO THE ATAXIC EFFECT OF ETHANOL

It has been well documented that drug associated cues are important fo r the development and expression of drug tolerance. The Pavlovian cond itioning analysis of tolerance emphasizes the importance of a drug-ass ociated cues to tolerance by equating a drug administration with a lea rning trial. According to this analysis, tolerance should be subject t o external inhibition, the disruption of a conditional response by a n ovel stimulus. We previously reported that tolerance to the ataxic eff ect of ethanol was attenuated by a novel strobe/noise presentation (31 ). In this article we report evidence of a compensatory CR in rats tol erant to the ataxic effect of ethanol as tested on the tilting plane. Both the compensatory CR and tolerance were disrupted by the presentat ion of a novel strobe/noise stimulus providing converging evidence tha t the attenuation of tolerance by a novel stimulus results from extern al inhibition of Pavlovian conditioning. The disruption of ethanol tol erance and the conditional response mediating tolerance was also appar ent when the novel omission of the strobe/noise stimulus was used as t he external inhibitor in rats made tolerant to ethanol with the stimul us on. Finally, we have shown that the disruptive effect of a novel st imulus on ethanol tolerance is decreased when there is a 10-day delay between the final tolerance development session and testing, demonstra ting that the interval between training and testing is important when assessing associative tolerance. (C) 1998 Elsevier Science Inc.