Effects of Adenosine on the Ionic Channel Activated by Metabolic Inhibition in Rabbit Ventricular Myocytes

  • Han, Jin (Department of Physiology & Biophysics, College of Medicine, Inje University) ;
  • Kim, Eui-Yong (Department of Physiology & Biophysics, College of Medicine, Inje University) ;
  • Ho, Won-Kyung (Department of Physiology & Biophysics, College of Medicine, Seoul National University) ;
  • Earm, Yung-E (Department of Physiology & Biophysics, College of Medicine, Seoul National University)
  • 발행 : 1996.06.30

초록

The objective of the present study was to characterize the role of adenosine in regulation of ATP-sensitive $K^+\;channel\;(K_{ATP}\;channel)$ activity in isolated rabbit ventricular myocytes using the patch clamp technique. Internal adenosine had little effects on KaTr channel activity. In an outside-out patch with intrapipette GTP and ATP, external adenosine stimulated $K_{ATP}\;channel$ activity. In an inside-out Patch with intrapipette adenosine, ATP reduced $K_{ATP}\;channel$ activity, and GTP stimulated $K_{ATP}\;channel$ activity. Adenosine receptor activation shifted the half-maximal inhibition Of $K_{ATP}\;channel\;from\;70\;to\;241\;{\mu}m$. These results Suggest that activation of adenosine receptors stimulates $K_{ATP}\;channels$ in rabbit ventricular myocytes by reducing the apparent affinity of the channel for ATP. The effect may be important for activating $K_{ATP}\;channels$ during early phase of myocardial ischemia.