Effects of [5-(2-Methoxy-5-fluorophenyl)furan-2-ylcarbonyl]guanidine (KR-32560), a Novel Sodium/Hydrogen Exchanger-1 Inhibitor, on Myocardial Infarct Size and Ventricular Arrhythmias in a Rat Model of Ischemia/Reperfusion Heart Injury

The cardioprotective effects of the novel sodium/hydrogen exchanger-1 (NHE-1) inhibitor KR-32560 {[5-(2-methoxy-5-fluorophenyl)furan-2-ylcarbonyl]guanidine} were studied in an anesthetized rat model of 30-min ischemia / 2.5-h reperfusion heart injury. KR-32560 (0.01 – 1 µM) dose-dependently inhibited NHE-1-mediated rabbit platelet swelling induced by intracellular acidification. KR-32560 at 0.1 and 1.0 mg/kg (i.v. bolus, given 10 min before ischemia) reduced infarct size from 65.9% (control) to 49.7% and 32.7%, respectively, while reducing the extension of myocardial injury (mm3/g of left heart weight) from 405.1 (control) to 302.9 and 185.4, respectively (all P