Neurosteroid modulation of arterial baroreflex function in the rostral ventrolateral medulla

Cheryl M. Heesch. Autonomic Neuroscience Volume 161, Issues 1–2, 26 April 2011, Pages 28–33 DOI: 10.1016/j.autneu.2010.10.002This article was interesting because it showed that a microinjection of 3α-hydroxy-dihdroprogesterone may alter the GABAA receptor sensitivity. They microinjected of 3α-hydroxy-dihdroprogesterone into the RVLM of female virgin rats and looked at blood pressure and renal sympathetic nerve activity (rsna). They found that 15 minutes following the microinjection of 3α-hydroxy-dihdroprogesterone significantly reduced the baroreflex rsna gain in response to hypotension. However, when the inactive isomer of 3β-hydroxy-dihdroprogesterone was microinjected into the rvlm it did not alter the baroreflex. These data suggests that 3α-hydroxy-dihdroprogesterone may alter the activity of the GABAA receptor in the RVLM. Since 3α-hydroxy-dihdroprogesterone can be synthesized in the brain it may be possible that the synthesis of this metabolite could be altered under different pathophysiological conditions. I think that this relevant to us because we don’t know how production of neurosteroids in the brain is altered in exercise and this could be another future potential avenue that may be pursued.-MD