Effect of amphetamine on behavioral patterns of obsessive-compulsive and addictive gambling in a rat marble test

Effect of astressin, a corticoliberin antagonist, on aggression and anxiety-fobic states in male rats reared in social isolation

Aim. Intraspecific behavior, emotional and explorative activity were investigated after intranasal administration of astressin, a non-selective antagonist of CRF receptors, in the male rats reared in social isolation from 21 to 93 days. Results. In the “resident-intruder” test there was an increased level of aggression and communications in isolated rats compared to grouped animals. After intranasal administration of astressin (20 μg in 20 μl), rats grown in isolation demonstrated an increase in aggression and decreased in communicability compared to intact animals reared in isolation. In the “open field” test a level of motor activity was increased in rats grown in isolation compared to grouped animals. The anxiety-phobic state, as well as behavior in an elevated plus maze, revealed enhance of anxiety and fear in rats reared in isolation. After astressin administration to isolated animals the levels of anxiety and fear significantly decreased. Conclusion. The results of the work revealed that the antagonist of the CRF receptor astressin disinhibited aggression, removing anxious and phobic state in male rats reared in social isolation. The results prove the necessity of taking into account CRF mechanisms in the formation of the social isolation syndrome and the possibility of using CRF receptor antagonists to control the central mechanisms of stress and dependence in ontogenesis.

Astressin, an antagonist of CRF receptors, reduces anxiety and fobial states in rats reared in social isolation conditions

The influence of intranasal administration of astressin, a nonselective antagonist of CRF receptors, on delayed effects of chronic social isolation in the five first weeks after mother leaving on explorative and emotional behavior in rats was studied. Social exposures were applied from 21st to 93rd days of life. The rats reared in social isolation demonstrated higher level of motor activity compared with control in open field test. The assessment of both anxiety and fobial state and behavior in elevated plus maze revealed higher levels in anxiety and fear in isolated rats. Intranasal administration of astressin (1 µg/1µl, 20 µl, 10 µl in every nostrils) reduced significantly anxiety and fear levels in isolated rats. Therefore, both anxiolytic and antifobial effects of astressin, a nonselective antagonist of CRF receptors, were demonstrated in rats exposured to social isolation stress. The results support the idea taking into account the corticoliberin mechanisms in formation of social isolation syndrome and possibilities of using CRF antagonists to control the central stress mechanisms and dependence in ontogeny.