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 monoxime (BDM) in preserving endothelium-dependent coronary artery relaxation during myocardial ischemia. MATERIALS AND METHODS: Langendorff-perfused rat heart model. Endothelium-dependent and independent relaxations were tested with infusion of 5-hydroxytryptamine (10(-6) mol/L) and sodium nitroprusside (10(-5) mol/L), respectively. Four groups of hearts (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 exposed to 30 mins of no flow ischemia (37 degrees C). Group 3 was perfused with cold (4 degrees C) nonoxygenated BDM (30 mins) and group 4 (control) was exposed to 30 mins of no flow ischemia alone. Left ventricular pressure (LVP), left ventricular pressure first derivative (dP/dt) and coronary basal flow were evaluated before treatment and after 30 mins of reperfusion. RESULTS: BDM perfusion alone (group 1) did not affect coronary reactivity. Preservation of endothelium-dependent and -independent relaxation was significantly enhanced after ischemia in groups 2 and 3 (BDM-treated) compared with group 4 (control). No significant benefit was found regarding LVP and dP/dt in all groups. Postreperfusion coronary flow was decreased in all hearts except the controls (group 4), suggesting a residual BDM intrinsic effect on coronary flow. CONCLUSION: These experiments suggest that BDM can enhance preservation of coronary artery endothelium-dependent and -independent relaxation during myocardial ischemia in the isolated rat heart.