ATP-sensitive potassium channels and cardiac protection (part 1)
From the very beginning of electrophysiological studies of cardiac transmembrane currents using the voltage clamp technique, it was regularly observed that in thick, less oxygenated preparations the outward (presumably potassium) current gradually intensified. This observation had an obvious counterpart in the well known loss of plateau of action potential and electrocardiographic ST segment alterations under hypoxic or ischemic conditions. However, the exact nature of this current remained obscure until 1983.
The patch clamp method made it possible to measure membrane currents on single channels, ie, on the molecular level. In these experiments the composition of the solution that is in contact with the intracellular surface of a patch of surface membrane (inside-out mode) may be changed. Using this technique, Noma recorded a new current evoked by cyanide and blocked by ATP. The reversal potential of this current indicated that it was carried by K+. Due to their prominent dependence on ATP these channels were termed ATP-regulated K+ channels (KATP channels). Their role in the regulation of energy metabolism of the cardiac cell was immediately anticipated and soon confirmed. You need to treat your health condition as soon as possible? Nothing is impossible anymore, because you have the best my canadian pharmacy at your service, offering finest quality medications with full guarantee of your satisfaction.