Norihiro Nagano, Yuji Imaizumi (*), Masaru Hirano and Minoru Watanabe
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Nagoya City University, Nagoya 467, Japan (*) To whom correspondence should be addressed.
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 10 microM NDGA was added to the bathing solution (pCa 7.0). The effect of NDGA was concentration-dependent in the range of 1 - 100 microM 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.
Ca2+-dependent K+ channel, Nordihydroguaiaretic acid, Coronary arterial smooth muscle
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