INHIBITION BY SKF 525A AND QUINACRINE OF ENDOGENOUS GLIBENCLAMIDE-SENSITIVE K-ENCLOSED XENOPUS-OOCYTES( CHANNELS IN FOLLICLE)

Effects of local anesthetics-related drugs, SKF 525A (proadifen, a cyt ochrome P450 inhibitor) and quinacrine (a phospholipase A(2) inhibitor ) on glibenclamide-sensitive K+ currents were investigated using nativ e Xenopus oocytes. SKF 525A and quinacrine suppressed cromakalim-induc ed/glibenclamide-sensitive K+ currents with IC50 values of 9.8 mu M an d 4.4 mu M, respectively. Inhibitors of either cytochrome P450 or phos pholipase A(2), which are structurally unrelated to local anesthetics, however, did not affect the K+ currents. Similar results were obtaine d for Y-26763-induced/glibenclamide-sensitive K+ currents. SKF 525A an d quinacrine block the glibenclamide-sensitive K+ currents by a mechan ism irrelevant to the inhibition of cytochrome P450 or phospholipase A (2) in oocytes.