The Induction of a Depression-Like State by Chronic Exposure to Ultrasound in Rats Is Accompanied by a Reduction in Gene Expression of GABAA-Receptor Subunits in the Brain

Abstract—We studied quantitative changes in the components of GABAergic system in Sprague–Dawley rats using an ultrasound model of a depression-like state induced by chronic action of randomly alternating ultrasonic frequencies of 20–45 kHz. We measured expression of the GABRA1, GABRA2, GABRA3, and GABRB2 genes coding the α1, α2, α3, and β2 subunits of GABAA-receptors, respectively, in the hippocampus, prefrontal cortex, mesencephalon, and amygdala after one, two, and three weeks of stress. The levels of relative expression of GABRA1, GABRA2, and GABRA3 genes decreased to a various extent in different brain structures depending on the duration of ultrasound exposure. Reduced relative expression of GABRA1 and GABRA3 genes was found after one week of chronic exposure to ultrasound, while the decrease in relative expression of GABRA2 was seen only after three weeks. The relative expression of GABRB2 remained unchanged. Thus, for the first time, we studied the dynamics of gene expression of GABAA-receptor subunits accompanying different stages of the development of a depression-like state in rats; this helped to reveal the relation between the detected changes and the duration of exposure to stress.