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. These results demonstrate changes in the functional dynamics of the dopaminergic and noradrenergic systems of the brain in conditions of abnormal calcium homeostasis in the body, which underlie abnormalities of conditioned reflex activity and the acquisition of the adaptive behavioral strategies.

[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. The results point to the deranged functioning of dopamine and noradrenaline brain systems as a result of disorders in calcium homeostasis. These shifts result in disorders of conditioning and development of an adaptive behavioral strategy.

[The effect of hyperparathyroidism on the function of the hypothalamo-hypophyseal-adrenocortical system in unilaterally adrenalectomized rats]. / Vliianie giperparatireoza na funktsional'noe sostoianie gipotalamo-gipofizarno-adrenokortikal'noi sistemy odnostoronne adrenaléktomirovannykh krys.

Hyperparathyroidism was shown to activate the hypothalamo-hypophyseal-adrenocortical system (HHACS) in rats, intensifying the compensatory adrenal hypertrophy in unilaterally adrenalectomised rats, rising the level of 11-oxycorticosteroids in their plasma and adrenal gland, activating the production of corticoliberin in hypothalamus and corticotrophin in hypophysis. The HHACS activity was the highest in 3-month-old rats.

[The reaction of the hypothalamo-hypophyseal-adrenal cortex system in rats to unilateral adrenalectomy in hypoparathyroidism]. / Reaktsiia gipotalamo-gipofizarno-adrenokortikal'noi sistemy krys na odnostoronniuiu adrenaléktomiiu pri gipoparatireoze.

Parathyroidectomy and subsequent hypocalcemia were shown to inhibit the response of the hypothalamo-hypophyseal-adrenocortical system (HHACS) to unilateral adrenalectomy, as expressed by a lesser compensatory hypertrophy of intact adrenal gland and a lower concentration of 11-oxycorticosteroids in adrenal gland and in plasma. The greatest activity of the HHACS was revealed in 3-month old rats. The data obtained suggest an interaction between parathyroid and adrenal glands.

[The function of the hypothalamo-hypophyseal-adrenal system in the progeny of parathyroidectomized rat dams]. / Funktsiia gipotalamo-gipofizarno-nadpochechnikovoi sistemy potomkov paratireoidéktomirovannykh krys-materei.

Parathyroidectomy in rats was found to lower the calcium level in the litter's blood plasma, activate the hypothalamo-hypophyseal-adrenal system post partum and reduce it in ontogenesis. The system's development and postnatal activity seems to depend on the homeostasis of calcium.