Особенности функционального состояния гипоталамо-гипофизарно-адренокортикальной системы у крыс линии Крушинского–Молодкиной

Abstract

The aim of present work was to evaluate functional state of the hypothalamic–pituitary–adrenal axis (HPA) in both naive control Wistar rats and Krushinsky-Molodkina (KM) rats, genetically prone to audiogenic epilepsy, and analyzed the changes of activity of HPA in KM rats during and after expression of audiogenic seizure (AGS). Obtained data demonstrated that the activity of corticotropin-releasing hormone (CRH) neurons in KM rats was reduced, due to the increased inhibitory effect of GABAergic neurons. In the anterior pituitary, we observed accumulation of proopiomelanocortin and adrenocorticotropic hormone (ACTH). However, basal levels of ACTH and corticosterone were equal in the blood in both naive KM rats and Wistar rats. Thus, the data indicate the disturbances in the interaction between the hypothalamus and the pituitary gland in KM rats, which can be one of the regulatory mechanisms for maintaining hormone concentrations in the blood. Analysis of AGS effects on HPA demonstrated increasing secretion of CRH and vasopressin into the portal system of KM rats and ACTH in the blood at clonus-tonus stages, which expresses in 6-10 seconds after sound stimulation. Therein corticosterone level was increased in KM rats during 24 hours. In Wistar rats, the sound stimulation did not change the levels of ACTH and corticosterone in the blood. Thus, we demonstrated specific activation of HPA in KM rats by AGS as a result of epileptiform activity overspreading in the brain that revealed participation of HPA is the expression of seizure activity.