[Effect of euphorigenic drugs on emotionally-positive brain systems]

Cocaine (10 mg/kg), amphetamine (1 mg/kg), diacetylmorphine (5 mg/kg), pentobarbital (3 mg/kg) and diazepam (1 mg/kg) caused in rats an activation of the reactions of electrical self-stimulation of the lateral hypothalamus, comparable by their pronouncement. All the drugs changed the pattern of histograms of durations distribution of pauses between self-stimulations, due primarily to a diminished number of long pauses. Psychodepressant drugs increased the number of long and superlong pedal pressings. A number of pairs of parameters with stable correlations was revealed, and their changes under the drugs effect were noted. The results of the study suggest that euphorigenic effect of the drugs is connected with the activation of reward system produced by them.