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Objective To investigate the effects of BmkTXKβ, a newly purified ’ long chain’ peptide inhibitor of K+ channels from the Chinese scorpion Buthus martensi Karsch (BmK), on the electrophysiological properties of isolated rabbit atrial myocytes.Methods The standard whole-cell patch-clamp technique was used to study the effects of multiple concentrations of BmkTXKp on potassium currents and action potentials.Results BmkTXKp produced concentration-dependent prolongation of action potential duration at 20%, 50%, and 90% repolarization (APD20,50,90) without any use-dependence. Meanwhile, it had no significant effect on RMP, APA, or Vmax(n =9). At a dose of 1 μmol/L, BmkTXKβ decreased lto by 41.4% (n = 10, P<0. 01) at a membrane potential of +50 mV [from (13.63±0.87) pA/pF to (7.98±0.78) pA/pF]. lto was reduced significantly with an IC50 value of 1.82μmol/L (95% confidence interval: 1.47 -2.17 μmol/L), in a clear concentration-dependent manner. BmkTXKp blocked IKS and lKs,tail with an IC50 of 20.15 μmo
Objective To investigate the effects of BmkTXKβ, a newly purified ’long chain’ peptide inhibitor of K + channels from the Chinese scorpion Buthus martensi Karsch (BmK), on the electrophysiological properties of isolated rabbit atrial myocytes. Methods The standard whole-cell patch-clamp technique was used to study the effects of multiple concentrations of BmkTXKp on potassium currents and action potentials. Results BmkTXKp produced concentration-dependent prolongation of action potential duration at 20%, 50%, and 90% repolarization (APD 20,50,90) without any Atm dose of 1 μmol / L, BmkTXKβ decreased 1 to by 41.4% (n = 10, P <0.01) at a membrane potential of +50 mV [from (13.63 ± 0.87) pA / pF to (7.98 ± 0.78) pA / pF] lto was significantly reduced with an IC50 value of 1.82 μmol / L (95% confidence interval: 1.47 - 2.17 μmol / L), in a clear concentration-dependent manner. BmkTXKp blocked IKS and lKs, tail with an IC50 of 20.15 μmo