Abstract
Effects of nordihydroguaiaretic acid (NDGA) on the Ca2+-dependent K+ channel (BK channel) were examined by the patch clamp technique in single smooth muscle cells of porcine coronary artery. The open probability of BK channels in inside-out patches increased by about 30 times at the holding potential of 0 mV, when 10μM NDGA was added to the bathing solution (pCa 7.0). The effect of NDGA was concentration-dependent in the range of 1—100μM and partly removed by washout. The enhancement of BK channels by NDGA was not observed when the cytosolic Ca2+ concentration was very low (pCa > 8.5). These results clearly indicate that NDGA possesses a BK channel opening property in coronary arterial myocytes.
