RESIDENT CARDIAC MAST-CELLS AND THE CARDIOPROTECTIVE EFFECT OF ISCHEMIC PRECONDITIONING IN ISOLATED RAT-HEART

Our study was designed to investigate the role of resident cardiac mas t cells in the cardioprotective effect of ischemic preconditioning. Is chemic/compound 48/80 preconditioning and treatment with compound 48/8 0, a mast cell degranulator (I mu g/ml), produced cardioprotective and antiarrhythmic effects in isolated perfused rat heart subjected to 30 -min global ischemia followed by 30-min reperfusion. Four episodes of ischemic/compound 48/80 preconditioning and compound 48/80 treatment m arkedly reduced the release of lactate dehydrogenase (LDH) and creatin e kinase (CK) in coronary perfusate and the incidence of ventricular p remature beats (VPBs) and ventricular tachycardia or fibrillation (VT/ VF) during the reperfusion phase. The release of mast cell peroxidase (MPO), a marker of mast cell degranulation in coronary perfusate incre ased immediately after ischemic and compound 48/80 preconditioning. Th e cardioprotective and antiarrhythmic effect of ischemic/compound 48/8 0 preconditioning was lost within 60 min. It is proposed that the card ioprotective effect of ischemic preconditioning, which lasts for 60 mi n in isolated rat heart, may be ascribed to degranulation of resident cardiac mast cells.