SIGNIFICANCE OF OPIOID, CANNABINOID, BRADYKININ RECEPTORS AND КАТP-CHANNELS IN THE CARDIOPROTECTIVE EFFECT OF ADAPTATION TO COLD

Highlights It has been shown that chronic adaptation to cold (28 days, +2 – +4°C) has a cardioprotective effect in in vivo model of myocardial ischemia/reperfusion injury in rats. Certain types of receptors and К АТ P -channels might be involved in mechanisms of this effect. Aim . To evaluate the role of opioid, cannabinoid, bradykinin receptors and the К АТ P -channels in the infarct-limiting effect of chronic adaptation to cold. Methods . The study involved male Wistar rats weighing 250–300 g. Rats (two in a cage) were placed in a refrigerator for 28 days. The temperature inside the chamber was +2 – +4 o C. The infarct-limiting effect of chronic adaptation to cold and its possible cancelation by receptor blockers was studied in a 45-minute coronary artery occlusion and a 120-minute reperfusion of the rat myocardium in vivo . The quantitative assessment of myocardial injury was determined by the necrotic zone to the area at risk (NZ/AAR) ratio. Results . We have found that К АТ P -channels are involved in the mechanism of the infarct-limiting effect of chronic adaptation to cold. Opioid, cannabinoid and bradykinin receptors are not involved in this effect. Conclusion . The obtained results have expanded our understanding of cold adaptation, as well as receptor pathways involved in the mechanism of ischemia/reperfusion injury resistance. Further studying of the signaling and receptor pathways of the infarct-limiting effect of cold adaptation will reveal molecules responsible for tolerance to ischemia/reperfusion injury. These molecules can be used to develop novel cardioprotective drugs for the treatment of acute myocardial infarction.