Abstract
The aim of our present study was to clarify the presence and the functional importance of ATP-sensitive K+ channel (KATP channel) in pig detrusor since the poor studies of KATP channel in pig detrusor smooth muscle cells.The patch clamp technique were used to investigate the properties of KATP channel. In the whole cell configuration, outward currents were induced by levcromakalim ( greater than 1 μM). The outward currents evoked by levcromakalim were abolished by glibenclamide, however CGRP, VIP, adenosine and somatostatin failed to induce simultaneous outward currents. Levcromaklim activated a channel with an unitary conductance of 12 pS in the cell-attached patch configuration but not in the cell-free patch configuration. An application of 1 mM guanosine 5'-diphosphate (GDP) re-activated the 12 pS channel in the cell-free patch configuration. These openings of 12 pS channel were inhibited by ATP ( 0.1 and 1 mM) and 1 μM glibenclamide. Our molecular study showed that KATP channel in pig detrusor is composed of Kir6.1 coupled with SUR 2A. It is concluded that the 12 pS K+ channel in pig urinary bladder smooth muscle cells is KATP channel composed of Kir 6.1 and SUR 2A. [J Physiol Sci. 2007;57 Suppl:S225]
