Repeated swim-stress reduces GABA_A receptor α subunit mRNAs in the mouse hippocampus

The effects of brief repeated swim stress on the expression of GABA_A receptor α₁ subunit mRNAs was investigated in the mouse. Adult male mice were exposed to repeated brief (10 min) swim-stress once daily for 7 or 14 days and the levels of GABA_A receptor α subunit mRNAs were quantified in the hippocampus 24 h after the last session by Northern analysis. Repeated swim stress for 14 days resulted in a 47.3% ± 6.5 and 39.8% ± 7.6 decrease in the levels of the 4.8 kb and 4.4 kb GABA_A receptor α₁ subunit mRNAs, respectively. While there was a trend toward a reduction in the level of GABA_A receptor α₁ subunit mRNAs following 7 days of repeated swim stress, the latter did not reach statistical significance. In contrast, no significant alterations in the levels of glutamic acid decarboxylase or β-actin mRNAs were observed at either time point. The reduction in GABA_A receptor α₁ subunit mRNAs following repeated swim stress may underlie similar alteration(s) in hippocampal GABA_A receptor density previously observed following repeated swim stress.