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  • Pretreatment with catecholamines can suppress severe ventricular arrhythmias in rats: Relevance to ischemic preconditioning (part 2)

Relevance to ischemic preconditioning (part 2)

In some recent studies, a different approach to triggering the IP-like protection pharmacologically has been demonstrated. Potentially deleterious substances, such as catecholamines, both endogenously released and exogenously applied, served as a tool to induce short term stress, without harmful consequences of the ischemic stress. Short application of catecholamines before the induction of long-lasting ischemia has been found to precondition the heart against postischemic myocardial stunning in rats , to reduce infarct size in rabbits , to suppress ischemia-induced arrhythmias in dogs and to trigger late cardiac protection . Most of the studies of the IP-like effect of catecholamines have used the recovery of contractile function or infarct size limitation as end-points, and only a few have investigated the effect of catecholamine-induced preconditioning on ischemic arrhythmias. Although several lines of evidence indicate that under certain conditions catecholamines can exert a protective effect in the myocardium, their role in the mechanisms of early and delayed protection has not been elucidated.There is evidence that catecholamines can stimulate the sodium-potassium pump and prevent the loss of potassium ions from cells during ischemia . Because disturbed homeostasis of ions plays a crucial role in the mechanisms of arrhythmogenesis , we hypothesized that any intervention capable of improving the function of the sodium pump may contribute to the suppression of arrhythmias. Accordingly, the present study was designed to investigate, first, whether pretreatment with catecholamines could afford immediate and delayed protection against ischemia in rat heart in vitro and in vivo, taking arrhythmias as an end-point; and second, whether Na+/K+-ATPase participates in this effect. Dreaming of a reliable pharmacy that could give you an opportunity to buy any amounts of Sale Cialis Professional with no prescription required and spend less money?

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