EFFECT OF CONDITIONAL STIMULUS ON MORPHINE WITHDRAWAL SIGNS IN THE RAT

The present investigation was undertaken to demonstrate the comparisons and contrasts of the conditional stimuli's (CS's) actions with those of morphine in morphine withdrawn rats. The study shows that specific stimuli altered behavioral and physiological withdrawal signs such as: hypothermia, shakes, ptosis, piloerection, writhing and aggression. Also, one stimulus was able to effect two biochemical measures (blood glucose and striatal homovanillic acid) similar to the action of morphine. Rats were given two equally spaced injections of morphine sulfate paired with different stimuli (bell, drug, oil of anise, saccharin). The stimuli were paired with an injection for 15-25 days. Twenty-four hours after the last morphine injection the appropriate stimulus was presented. The rats learned to increase their body temperature, reduce wet shakes, increase ptosis, reduce writhing and reduce aggressive responses following the presentation of oil of anise. The bell stimulus only increased temperature. The gustatory stimulus increased temperature and the drug stimuli had no effect on withdrawal signs. The changes observed were specific only to animals that had the respective stimuli paired with morphine prior to challenge treatment. The duration of the CS in the oi l of anise study was important, the onset required a time period of greater than 2 min