THE VENOM OF SCORPION B-MARTENSI SELECTIVELY INHIBITS TRANSIENT OUTWARD K-V(+) CHANNEL CURRENTS IN NG108-15 CELLS( CURRENTS IN NEONATAL RATVENTRICULAR CELLS AND K)

In this communication, the effects of the venom and/or minimolecular c omponent of Chinese scorpion Buthus martensi Karsch (BmK) on nine kind s of K+ or Cl- channels have been scanned under voltage-and patch-clam p recording conditions. The venom showed weak blockade to voltage-gate d K+ channels in NG108-15 cells, while a reversible blocking effect of the minimolecular component on transient outward K+ currents was dist inctly observed in neonatal rat ventricular cells. Among nine channels tested, little effect was observed on the other seven channels. The p resent results suggest that Chinese scorpion BmK contains a novel clas s of active minimolecule, which selectively binds to K+ channel family , in addition to the known polypeptides which bind to Na+ channels.