ATP-sensitive potassium channels and cardiac protection (part 14) / proventil inhaler
The late memory may be an adaptive process based on altered proteosynthesis. Indeed, it has been proved that ‘stress proteins’ with protective effects (eg, antioxidant) form at the time of ‘second window of protection’ . It is assumed that the underlying specific gene expression is initiated by activation of PKC and very likely of other kinases.
It has repeatedly been shown that activation of Katp channels is closely related to preconditioning , and that adenosine and Katp channels may synergistically interact in forming the memory of preconditioned cells . The most convincing evidence is perfect mimicking of ischemic preconditioning by application of Katp channel activators (openers).These drugs prevent ischemia-induced ATP decay, reduce infarct size and significantly improve recovery from reperfusion injury . An illustrative example of the cardioprotective effect of a Katp opener in isolated guinea-pig ventricle was presented by Cole et al . Pinacidil administered during ischemia prevented increase of resting tension, transient dysrhythmias and incapacity to recover contractile tension upon reperfusion. Cardioprotective effects of nicorandil were also confirmed in a clinical study demonstrating a reduction of ST segment elevation during percutaneous transluminal coronary angioplasty (PTCA) . Efficient treatment that is now easy to get and fast to receive: you can finally buy your proventil inhaler knowing that it will be there soon and you will start the treatment knowing this is in fact the efficient medicine you needed an can pay a lot less for.
The beneficial effects of ischemic preconditioning, adenosine or Katp channel activators are opposed and even completely blocked by Katp inhibitors such as glibenclamide . Also, clinical studies in patients undergoing PTCA demonstrated that glibenclamide deprived the preconditioning procedure (repeated short term balloon inflation) of its protective effect .