Fig. 1. Effects of thiamylal on the adenosine triphosphate–sensitive potassium (K^ATP) channel activities in the cell-attached configuration. Membrane potentials were clamped at −50 mV. The dashed line is the zero current level. (A ) No significant current was observed before 2,4-dinitrophenol (DNP) treatment. DNP in the bath solution activated K^ATPchannels. (B ) DNP-induced K^ATPchannel activity was inhibited by glibenclamide. This blockade was reversible, and the channel activities were restored by washing out glibenclamide. (C ) Dose-dependent effects of thiamylal on K^ATPchannels. The channels show a decreased open probability as thiamylal concentration is increased.