title: Influence of Thromboxane A2 on the Regulation of Adenosine Triphosphate-Sensitive Potassium Channels in Mouse Ventricular Myocytes.
abstract: OBJECTIVE
  Adenosine triphosphate (ATP)-sensitive potassium (KATP) channels play an important role in myocardial protection. We examined the effects of thromboxane A2 on the regulation of KATP channel activity in single ventricular myocytes.
  
  
  METHODS
  Single ventricular myocytes were isolated from the hearts of adult Institute of Cancer Research (ICR) mice by enzymatic digestion. Single channel activity was recorded by excised inside-out and cell-attached patch clamp configurations at -60 mV holding potential during the perfusion of an ATP-free K-5 solution.
  
  
  RESULTS
  In the excised inside-out patches, the thromboxane A2 analog, U46619, decreased the KATP channel activity in a dose-dependent manner; however, the thromboxane A2 receptor antagonist, SQ29548, did not significantly attenuate the inhibitory effect of U46619. In the cell-attached patches, U46619 inhibited dinitrophenol (DNP)-induced KATP channel activity in a dose-dependent manner, and SQ29548 attenuated the inhibitory effects of U46619 on DNP-induced KATP channel activity.
  
  
  CONCLUSIONS
  Thromboxane A2 may inhibit KATP channel activity, and may have a harmful effect on ischemic myocardium.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: In Seok
authors.initials: IS
authors.lastname: Jeong
authors.affiliation: Department of Pediatrics, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Hwa Jin
authors.initials: HJ
authors.lastname: Cho
authors.affiliation: Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Jeong Gwan
authors.initials: JG
authors.lastname: Cho
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Sang Hyung
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Kook Joo
authors.initials: KJ
authors.lastname: Na
authors.affiliation: Department of Pharmacology, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Jong-Keun
authors.initials: JK
authors.lastname: Kim
keywords: Cardiac; KATP channels; Myocytes; Thromboxane A2