[Anxiogenic and mnestic effects of corticoliberin and its analogs introduced into the brain ventriculi of rats]

The behavioral effects of native human corticotropin-releasing hormone (CRH) and its agonists D-Glu-20 (R1) and D-Pro-5 (R2) introduced (0.01 - 1 microg) into the lateral brain ventriculi of Sprague-Dowley rats have been studied in the open field, dark - LIGHT, Y-maze, and place preference tests. The different effects of CRH and its agonists on the anxiety level and short-term memory were revealed. D-Glu-20 (an R1 agonist of CRH) acted as an anxiogen in the open field and dark - LIGHT tests. D-Pro-5 (an R2 agonist of CRH) did not cause the typical anxiogenic effect, but produced a nonspecific suppression of behavior. D-Pro-5 only in high doses decreased the number of visits into the LIGHT box in the dark - LIGHT test. At the same time, this compound enhanced the short-term memory to a maximum degree and prevented the memory loss induced by diazepam. The data obtained are in agreement with the published data about differential participation of R1 and R2 receptor systems of CRH in the regulation of emotional and mnestic components of behavior. The anxiogenic action of CRH is connected with the activation of R1 receptors of CRH.