| Abstract: | Rats received paired injections of either ethanol or saline as the conditioned stimulus and lithium chloride as the unconditioned stimulus (US) in a Pavlovian differential conditioning paradigm. Lithium chloride evoked a large deceleration in heart rate (80-100 beats per minute) as an unconditioned response. As a result of 10 conditioning trials, the substance paired with LiCl elicited a lower average heart rate than that elicited by the unpaired substance. Moreover, animals that received ethanol-LiCl injections subsequently were more averse to the taste of ethanol than animals receiving saline-LiCl pairings. However, there were no differences in ethanol's ability to serve as the US to induce an aversion to a novel flavor solution (i.e., the Avfail phenomenon was not observed). The overall pattern of results underscores the value of using multiple indexes of learning in drug-drug conditioning paradigms. |
