ALCOHOL ABOLISHES POST-STRESSOR AVERSION IN MALE RATS (POTENTIAL ROLE OF к-OPIOID RECEPTORS)
Medicinskij akademiceskij ?urnal (Meditsinskij Akademitsjeskij Journal)
The probability of alcohol consumption by humans and experimental animals increases immediately after impact of stressors and remains at high level for some time. Neurobiological basis of this pattern is the effect of stress hormones on the mesolimbic system which is the core of the reward system in the brain that initiates learning processes. Literature data suggest that formation of aversive reactions depends on the system of dynorphin and к-opioid receptors which activates during the stress
... during the stress reaction. The purpose of this study was to investigate effect of alcohol administration on the post-stressor condition of the reward system and to clarify the role of к-opioid receptors in this. Experiment 1 aimed to investigation of post-stressor condition of the reward system in male and female rats and the influence of alcohol administration on it. Experiment 2 aimed to study whether alcohol affects the known from the literature aversive effect of che mical stimulation of к-opioid receptors as a model of post-stressor aversion. Methods. Appearance of preference or aversion to place where the rats were after action of the stressor was the indicator of the state of their reward syste m (place preference test). Result of the experiment 1. Condition of the reward syste m in the male rats was aversive 15 minutes after the end of the stressor action that caused avoidance of the context of environment in the future. Administration of alcohol after the end of the stressor action ceased this effect. Result of the experiment 2. Unlike the post-stressor aversion alcohol does not influence the aversion caused by stimulation of к-opioid receptors. Conclusion. Results of the study suggest that there is the aversive phase of the post-stressor state in the male rats that leads to formation of aversive associative reaction to the context of environment. Alcohol administration abolishes this phase. The involve ment of к- opioid receptors in this effect of alcohol is doubtful. But the final conclusion is possible only after direct experiment using antagonists.