MECHANISM UNDERLYING POTENTIATION BY PROGESTERONE OF THE KAINATE-INDUCED CURRENT IN CULTURED NEURONS

The effect of the neurosteroid progesterone on the kainate receptor-me diated response was studied in cultured chick spinal cord neurons usin g the whole-cell voltage-clamp recording technique. Progesterone rapid ly and reversibly potentiates the kainate-induced current in a dose-de pendent manner, with an EC50 of 35 mu M and a maximal potentiation of 30%. Potentiation of the kainate response by extracellularly applied p rogesterone is not significantly affected by inclusion of a saturating concentration of progesterone in the electrode buffer, indicating tha t progesterone acts at the extracellular surface of the membrane. Furt hermore, progesterone enhances the kainate maximal response with littl e effect on the kainate EC50. (C) 1998 Elsevier Science B.V.