Glucocorticoid modulates the sensitivity of the GABAA receptor on primary afferent neurons of bullfrogs.
With intracellular and voltage-clamp recording techniques, we have demonstrated that the glucocorticoids, prednisolone and hydrocortisone at a concentration of 5 microM to 1 mM, reversibly depressed gamma-aminobutyric acid (GABA)-induced responses on primary afferent neurons of bullfrogs. An analysis with dose-response curves revealed that the glucocorticoids decreased the sensitivity of the GABAA receptor in a non-competitive manner. We suggest that glucocorticoids act as an antagonist of the GABAA receptor on primary afferent neurons, probably by reducing the number of functional GABAA receptor ionic channel complexes.
D000818:Animals; D003864:Depression, Chemical; D004305:Dose-Response Relationship, Drug; D005727:Ganglia, Spinal / Q000187:drug effects*; D006854:Hydrocortisone / Q000494:pharmacology*; D011239:Prednisolone / Q000494:pharmacology*; D011892:Rana catesbeiana; D011963:Receptors, GABA-A / Q000187:drug effects*
D011963:Receptors, GABA-A; D011239:Prednisolone; D006854:Hydrocortisone