[Level of neuroactive steroids in the brain, and gender-related differences in formation and decrease of conditioned reflex in rats].

We investigated gender-related differences in dynamics of the brain sexual steroids during learning and the decrease of conditioned reflex in the modeling experiment. It was revealed that, before training to conditioned reflexes, females manifested a greater anxiety than males. Significant differences between males and females in formation of the conditioned reflex of passive avoidance were not revealed, whereas the conditioned response decrease were by 2-3 days faster in male rats than in females.

[Sex-related peculiarities of conditioned reflex activity and dynamics of sex steroids in the brain].

Sexual peculiarities of dynamics of brain sex steroids in the process of learning and extinction of the conditioned reflex of passive avoidance have been studied in model experiment. Prior to learning of conditioned reflex, females were found to be distinguished by manifestation of anxiety and fear as compared with males. At formation of the conditioned reflex, no significant sex differences were detected between males and females, whereas extinction of the conditioned reaction of passive avoidance in rat males occurred by 2-3 days faster than in females.

Interaction of total blood calcium levels and brain catecholamines during the formation and reinforcement of memory traces in hypoparathyroidism.

Interactions between the total blood calcium level and catecholamine contents in limbic brain structures during the formation and extinction of a conditioned passive avoidance reflex were studied in rats with hypoparathyroidism. Impairments of calcium support for the processes of conditioned reflex activity were seen after removal of the parathyroid glands. Animals with hypoparathyroidism not only showed changes in basal dopamine and noradrenaline levels in limbic structures, but also impairments of catecholamine dynamics during the acquisition and forced extinction of a conditioned passive avoidance reflex.

[Correlation between the levels of calcium in the blood and catecholamines in the brain during memory formation and fixation in hypoparathyreosis].

Relationship between the blood level of calcium and the level of catecholamines in the brain limbic structures was studied in passive avoidance conditioning and extinction in rats with hypoparathyreosis. After parathyroidectomy, conditioning processes were shown to be impaired as a result of a disorder of calcium supply. In hypoparathyreosis, not only the basic dopamine and noradrenalin levels change, but catecholamine dynamics in learning and forced extinction of a passive avoidance reaction shifts.