Effect of prenatal use of methyldopa and phenibut on the formation of stressor reactiity of HPA axis in adult rats under normal conditions and in disturbed state as a result of prenatal stress

Abstract

The author has studied the gender features of hormonal response of adrenal cortex to acute test-stress (one-hour immobilization) in adult rats of both genders  whose mothers were exposed during the last week of pregnancy to immobilization stress under use of Methyldopa (a noradrenalin antagonist) or Phenibut (a GABA  agonist). Methyldopa or Phenibut administration to pregnant rats before their stressing prevented development of a disturbed adrenocortical response to acute  stress in adult offspring, caused by prenatal stress. Hormonal response to adrenocortical stressor stimulation approached the parameters characterizing normal  animals: in males by increasing post-stressor corticosterone level in blood plasma, and in females by decreasing it. Administration of these drugs to pregnant rats  that did not undergo immobilization stress had a modifying effect on the formation of gender differences in stressinduced HPA axis activity in adult offspring. These  findings point out a significant role of noradrenergic amd GABAergic systems of the brain in prenatal programming of stress reactivity of the HPA axis under normal  conditions and its disturbance due to prenatal stress.