[Conditioned reflexes in rats after 5-minute arrest of blood circulation]

Abstract

Neurological recovery and conditioned activity were studied in rats resuscitated after five-minute circulation cessation caused by intrathoracal clamp of the heart vascular bundle. The dynamics of disappearance of neurological deficit was evaluated according a scale of 19 parameters of the general state of animals where number 100 meant the death of the brain and number 0 meant recovery. In the course of 8 months after resuscitation, in reanimated rats and simultaneously in intact (control) ones, an alimentary instrumental conditioned reflex was elaborated and then changed to a defensive one; passive and acute extinction of both reflexes was also carried out. In most of the rats the neurological recovery was completed rapidly within 3-4 hours. In reanimated animals, both instrumental conditioned reflexes were acquired in the same way as in the intact rats. Quantitative evaluation of the dynamics of conditioning and extinction allowed to see that elaboration of the alimentary reflex in reanimated rats proceeded faster and its change to the defensive one, and acute extinction of both kinds of conditioned reflexes went slower than in intact animals. A conclusion is drawn that even a short-term circulation cessation compatible with complete and rapid compensation of visible neurological disorders causes long-term disturbances of conditioned activity manifested in weakening of inhibitory processes.