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Pretreatment with catecholamines can suppress severe ventricular arrhythmias in rats: DISCUSSION (part 4)

On the other hand, it has recently been demonstrated that catecholamines can enhance cell-to-cell mechanical and electrical coupling and attenuate conduction inhomogeneity and desynchronization of cells being a source of fibrillation during ischemia . This was based on the observation of catecholamine-induced increased spread of fluorescent dye between cardiomyocytes under hypoxic conditions and high calcium concentration , and it may provide a further explanation for the suppression of arrhythmias demonstrated in our study.
In this study of the isolated heart we did not explore the relationship between the preconditioning-like anti-arrhythmic effect and changes in hemodynamics. These transient changes in heart rate and perfusion pressure (due to coronary vasoconstriction) may be sufficient to produce a certain degree of demand ischemia leading to preconditioning. On the other hand, we cannot rule out a direct adrenergic effect on the myocardium triggering adaptive processes mediated by the signal transduction system.
It is believed that both types of protection may share a signal transduction pathway albeit with different effector pathways. The key event in these mechanisms may be that alpha-adrenergic stimulation causes translocation of protein kinase C (some of its isoforms) from the cytosol to the sarcolemma with consequent activation and phosphorylation of some (as yet unknown) proteins mediating immediate protection . In addition, different isoforms can be translocated into the nucleus, where they can activate many oncogenes and transcription factors with a consequent synthesis of some protective proteins believed to be responsible for the late phase of protection (reviewed in 2). You now have access to the best pharmacy that always does what it promises and sells finest quality drugs that you will benefit from: buy ortho tri-cyclen online buy now and see for yourself how easy and convenient it could be to shop for yourdrugsonline.

Category: Cardiology

Tags: Catecholamines, Na+/K+ -ATPase, Preconditioning, Ventricular arrhythmias

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