Tolerance to Pentabarbital and Sensitation to Amphetamine Due to Assoctative Processes

Abstract

It has been suggested that drug tolerance is arnenable to an analysis based on Par’lovian conditioning processes. Conditioned tolerance has been demonstrated with several dru gr. ami the role of contextttal stimuli in the establishment of conditioned tolerance has been discussed extensively.The present stndy demonstrated conditioned tolerance as a function of the type of contextual stirnulí; it also assessed the effects of amphetamine on subjects tolerant to pentobarbital. In Experitnent 1, rats received 20 pentobarbital injectons in the presence of dsstmncttve contex tttal stitnult Then, they were given two tolerance tests of the sedative effects of pentobarbital (30 and 50 ntg/kg). These tests were condztcted itt the presence of contextual stimuli associated with drug injections and satine inlections. Rats tested under dr-ug-associated contextual sti,nuli showed tolerance, but they were not tolerant when tested under saline-associated contextual stitnuli. Itt Experintent 2, rats were trained to drinh evaporated ntilk. Then, they were given seven pentobarbital injections itt a dis¬tintive environntent and seven satine injections itt a different environ,nent. Titen, they were given three tnilk consuntption tests. During tite first test tite rats were allowed to drink without tite effects of drugs; during the second test sessions tite rats were injected tite 4 mg/hg of amphetamine and were tested under the presence of stimuli associated witit pentobarbital injectiøns; the ¡art was conducted under the effects of tite sorne dore of a,npitetamine ¿mt itt tite presence of stimuli.