Simultaneous blockade of the cyclooxygenase and L-arginine-nitric oxide pathways prevents the antiarrhythmic effects of classical preconditioning (part 2)

classical preconditioning (part 2)

These mediators, generated during the preconditioning stimulus and acting in concert, are then responsible for the antiar-rhythmic protection during a subsequent more prolonged ischemic insult . We have demonstrated an antiar-rhythmic, nitric oxide-mediated effect of bradykinin in myocardial ischemia and a role for it in ischemic preconditioning . Bradykinin has also been found to be involved in the protective effect of preconditioning in reducing infarct size in rabbits and in enhanced post-ischemic myocardial recovery in isolated rat hearts . This latter effect was attributed to the release of both prostacyclin and nitric oxide.Evidence that nitric oxide and prostacyclin might be involved in the antiarrhythmic protection of preconditioning came initially from our previous studies in which either inhibition of the L-arginine-nitric oxide pathway by NG-nitro-L-arginine methyl ester (L-NAME) or blockade of the cyclooxygenase pathway by sodium meclofenamate markedly attenuated the antiarrhythmic effects of preconditioning. Although protection against arrhythmias was markedly attenuated after the separate inhibition of either of these pathways, it was not fully reversed. In the present study we therefore examined whether the early protective effects of preconditioning against arrhythmias are completely abolished if both the L-arginine-nitric oxide and the cyclooxyge-nase pathways are blocked simultaneously. A preliminary account of these results was presented at the 15 th World Congress of the International Society for Heart Research in Prague, Czech Republic . Online shopping will cost you less money and will take less time, because you can find efficient help allergies with generous discounts at the pharmacy that proved its reputability and desire to help by offering best level of service and most efficient drugs.

Category: Cardiology

Tags: Cyclooxygenase pathway, Ischemic preconditioning, L-arginine-nitric oxide pathway

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