Effects of single immobilization stress on the GABA metabolism and behavior of pregnant and nonpregnant female rats during early post-stress period

Abstract

We studied the effects of a single immobilization stress on pregnant (9th or 10th day of pregnancy) and nonpregnant female rats in the early post-stress period (1 day after a stress). We analyzed the changes in behavioral responses, activity of antioxidant systems (ASs), and GABA metabolism. It was shown that control unstressed pregnant rats had a higher level of locomotor and exploratory activities and a lower level of anxiety and emotional tension as compared to nonpregnant rats. The pregnant rats were characterized by a higher activity of glutamate decarboxylase (GDC). In nonpregnant rats in the early post-stress period, the locomotor and exploratory activity and “risk behavior” increased, while anxiety decreased. These changes were not related to changes in the GABA metabolism, while the efficacy of ASs was increased. In the group of pregnant rats, the consequences of immobilization included only a significant increase in the activity of GABA transaminase (GABA-T). Thus, pregnant rats had higher stress resistance than the nonpregnant rats, according to behavioral indices and activities of systems of GABA metabolism and ASs.