Do antiepileptics phenytoin, carbamazepine, and loreclezole show GABAA receptor subtype selectivity in rat brain sections?

摘要: [35S]t-Butylbicyclophosphorothionate ([35S]TBPS), a convulsant site ligand of GABAA receptors, was used in autoradiography with rat brain sections to test suggested receptor subtype-selective actions antiepileptics phenytoin, carbamazepine and loreclezole on native receptors. At maximal 100 μM concentration, both phenytoin decreased [35S]TBPS binding only by 20%, indicating that their low potency efficacy prevents use as α1 subunit-identifying compounds. Ten did not affect the binding, but further increase concentration strongly it. The action loreclezole, assumed reflect β2/3 subunit-containing varied from region region, effects were unrelated regional expression profiles β subunit variants. We conclude autoradiographic assay neither carbamazepine, nor are useful tools characterizing heterogeneity receptors rats exhibits high, pharmacologically relevant efficacy.