Cardioprotective effects of novel tetrahydroisoquinoline analogs of nitrobenzylmercaptopurine riboside in an isolated perfused rat heart model of acute myocardial infarction

Cardioprotective effects of novel tetrahydroisoquinoline analogs of nitrobenzyhmercaptopurine riboside in an isolated perfused rat heart model of acute myocardial infarction. Ani J Physiol Heart Circ Physiol 292: H2921-H2926 2007. First published February 9, 2007: doi:10.1152/ajpheail.01191.2005. - We have investigated the cardioprotective effects of novel tetrahydroisoquinoline nitrobenzylmercaptopurine riboside (NBMPR) analog nucleoside transport (NT) inhibitors. compounds 2 and 4, in isolated perfused rat hearts. Langendorff-perfused heart preparations were subjected to 10 min of treatment with compound 2, compound 4, or vehicle (control) followed by 30 min of global ischemia and 120 min of reperfusion. For determination of infarct size, reperfusion time was 180 min. At I compounds 2 and 4 provided excellent cardioprotection. with left ventricular developed pressure (LVDP) recovery and end-diastolic pressure (EDP) increase of 82.9 +/- 4.0% (P < 0.001) arid 14.1 +/- 2.0 mmHg (P < 0.03) for compound 2-treated hearts and 79.2 +/- 5.9% (P < 0.002) and 7.5 +/- 2.7 mmHg (P < 0.01) for compound 4-treated hearts compared with 41.6 +/- 5.2% and 42.5 +/- 6.5 mmHg for control hearts. LVDP recovery and EDP increase were 64.1 +/- 4.2% and 29.1 +/- 2.5 minHg for hearts treated with 1 mu M NBMPR. Compound 4 was the best cardioprotective agent. affording, significant cardioprotection, even at 0.1 mu M, with LVDP recovery an EDP increase of 76.0 +/- 4.9% (P < 0.003) and 14.1 +/- 1.0 mmHg (P < 0.03). At mu M, compound 4 and NBMPR reduced infarct size. with infarct area-to-total risk area ratios of 29.13 +/- 3.17 (P < 0.001) for compound 4 and 37.5 +/- 3.42 (P < 0.01) for NBMPR vs. 51.08 +/- 5.06% for control hearts. Infarct size was more effectively reduced by compound 4 than by NBMPR (P < 0.02). These new tetrahydroisoquinoline NBMPR analogs are not only potent cardioprotective agents but are, also, more effective than NBMPR in this model.