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Effects of berberine on potassium currents in acutely isolated CA1 pyramidal neurons of rat hippocampus

2003; Elsevier BV; Volume: 999; Issue: 1 Linguagem: Inglês

10.1016/j.brainres.2003.11.036

1872-6240

Fang Wang, Gang Zhao, Lan Cheng, Hongyi Zhou, Liying Fu, Wei-xing Yao,

Cardiac electrophysiology and arrhythmias

The effects of berberine, an isoquinoline alkaloid with antiarrhythmic action, on voltage-dependent potassium currents were studied in acutely isolated CA1 pyramidal neurons of rat hippocampus by using the whole-cell patch-clamp techniques. Berberine blocked transient outward potassium current (IA) and delayed rectifier potassium current (IK) in a concentration-dependent manner with EC50 of 22.94+/-4.96 microM and 10.86+/-1.06 microM, Emax of 67.47+/-4.00% and 67.14+/-1.79%, n of 0.77+/-0.08 and 0.96+/-0.07, respectively. Berberine 30 microM shifted the steady-state activation curve and inactivation curve of IA to more negative potentials, but mainly affected the inactivation kinetics. Berberine 30 microM positively shifted the steady-state activation curve of IK. These results suggested that blockades on K+ currents by berberine are preferential for IK, and contribute to its protective action against ischemic brain damage.