2,3-BUTANEDIONE MONOXIME PRESERVES CORONARY-ARTERY ENDOTHELIUM-DEPENDENT RELAXATION DURING MYOCARDIAL-ISCHEMIA IN THE ISOLATED RAT-HEART

OBJECTIVE: To evaluate the potential benefit of 2,3-butanedione monoxi me (BDM) in preserving endothelium-dependent coronary artery relaxatio n during myocardial ischemia. MATERIALS AND METHODS: Langendorff-perfu sed rat heart model. Endothelium-dependent and independent relaxations were tested with infusion of 5-hydroxytryptamine (10(-6) mol/L) and s odium nitroprusside (10(-5) mol/L), respectively. Four groups of heart s (n = 6) were used. Group 1 was perfused with BDM (25 mmol/L) without ischemia for 30 mins. Group 2 was perfused for 10 mins with BDM and e xposed to 30 mins of no flow ischemia (37 degrees C). Group 3 was perf used with cold (4 degrees C) nonoxygenated BDM (30 mins) and Group 4 ( control) was exposed to 30 mins of no flow ischemia alone. Left ventri cular pressure (LVP), left ventricular pressure first derivative (dP/d t) and coronary based flow were evaluated before treatment before trea tment and after 30 mins of reperfusion. RESULTS: BDM perfusion along ( group 1) did not affect coronary reactivity. Preservation of endotheli um-dependent and independent relaxation was significantly enchanced af ter ischemia in groups 2 and 3 (BDM-treated) compared with group 4 (co ntrol). No significant benefit was found regarding LVP and dP/dt in al l groups. Postreperfusion coronary flow was decreased in all hearts ex cept the controls (group 4), suggesting a residual BDM intrinsic effec t on coronary flow. CONCLUSION: These experiments suggest that BDM can enchance preservation of coronary artery endothelium-dependent and in dependent relaxation during myocardial ischemia in the isolated rat he art.