Regulatory volume decrease (RVD) is essential for the survival of animal cells. The aim of this study was to observe the RVD process in rat ventricular myocytes, and to determine if the KATP channels are involved in the RVD process in these cells. By using reverse transcriptase polymerase chain reaction and Western blot analysis, we demonstrated that there are two types of KATP channels expressed in rat ventricular myocytes: Kir6.1 and Kir6.2. When rat cardiac myocytes were exposed to hypotonic solution, cell volume increased significantly within 15 min and then gradually recovered. This typical RVD process could be inhibited by a Cl– channel blocker (0.5 mM 9-anthracene-carboxylic acid , 9-AC), a K+ channel blocker (5.0 mM CsCl) and a KATP channel blocker glibenclamide (10 μM). Electrophysiological results showed that hypotonic solution activated a whole-cell current, which had similar biophysical characteristics with KATP opener (pinacidil)-induced currents. This current could be blocked by glibenclamide. Our data suggested that the RVD process in rat ventricular myocytes is dependent on the activation of K+ channels, and that KATP channels are involved in this process., L. Shi ... [et al.]., and Obsahuje seznam literatury