CONTINGENT DRUG TOLERANCE - DIFFERENTIAL TOLERANCE TO THE ANTICONVULSANT, HYPOTHERMIC, AND ATAXIC EFFECTS OF ETHANOL

The kindled-convulsion model of epilepsy was used to study contingent tolerance to ethanol's (1.5 g/kg; IP) anticonvulsant, hypothermic, and ataxic effects in adult male rats. In the present experiments, three groups of amygdala-kindled rats received a series of bidaily (one ever y 48 h) convulsive stimulations: one group received ethanol 1 h before each stimulation; one group received ethanol 1 h after each stimulati on; and another group served as the saline control. Tolerance to ethan ol's anticonvulsant effect (Experiments 1 and 2) was greatest in those rats that received ethanol before each convulsive stimulation; wherea s, tolerance to ethanol's hypothermic (Experiments 1 and 2) and ataxic (Experiments 2) effects developed in both groups that received ethano l. These results were predicted on the basis of the drug-effect theory of drug tolerance: the theory that functional drug tolerance is an ad aptation to the disruptive effects of drugs on concurrent patterns of neural activity, not to drug exposure per se.