Stress-induced elevations of y-aminobutyric acid type A receptor-active steroids in the rat brain

ROBERT H. PURDY, A. LESLIE MORROW, PERRY H. MOORE, JR., AND STEVEN M. PAUL. Proc. Nati. Acad. Sci. USA. Vol. 88, pp. 4553-4557, May 1991 Neurobiology. They investigated the effects of stress on the production of pregestrone metabolites in the brain. They used adrenectomized and non-adrenalectomized rats in order to determine how csf levels of progesterone, allopregnanolone and pregnanolone in rats were altered in response to swim stress. They used a couple of techniques such as chromatography, and RIA or Radioimmuno assay. What they found was that in the adrenalectomized, adrenalectomized stressed and controls had undetectable amounts of allotetrahydroDOC in plasma and cortex, however the stressed rats had significant enhanced levels of allotetrahydroDOC in both cortex and plasma. As for progesterone was not altered in response to stress when compared to the control group however the adrenalectomized rats had significantly lower progesterone when compared to the control rats. As for the allopregnanolone, in response to swim stress the level was significantly higher when compared to control animals in the cortex and plasma. Another interesting finding is that the in the adrenalectomized rats there was reduced allopregnanolone. The most important point I got from this article is that allopregnanolane and allotetrahydroDOC have the ability to bind to the benzodiazepine site on the GABA receptor, thus potentiating the effects of GABA. Since it seems that doing a adrenalectomy, abolishes the increase in these steroid metabolites, adrenal gland may be important to modulating GABAergic mechanisms in the brain. -MD