Background: This stu dy was designed to invest igate the ef· feet s of th e select ive endothelin-Areceptor antagonist BQ123 on myocardial and endothe lial funct ion after rever sible deep hypot hermic ischem ia and reperfusion . Methods: Isogenic intra-abdomina l het erotopic hea rt transplantati on was perfo rmed in l ew is rat s. Afte r one hour of cold ischemic preservation reperfusia n was sta rte d afte r a pplicatio n of either saline vehicle or BQ l23 (l !lmol/l).left-ventricular pressure-volum e relat ions and myocardial blood flow were asse sse d aft er one and 24 hour s of reperfu sion . Responses to endothelium-de pende nt vasodilator acetylcholine and endot helium-inde pende nt vaso dilato r sodium nitropru sside we re also det ermin ed. Results: BQ123 significant ly improved myocardial co ntract ility. as indicated by the leftward shift of the systolic pressure-volume relation and significantly increased myocardial blood flow during ea rly reperfu sion (p < 0.05). Although myocardial functi on and baseline myocardial blood flow were similar in both gro ups after 24 hour s of reperfuslon, endothelium-depende nt vasod ilatation was st ill sig nificantly higher in the BQ 123 group (p < 0.05). Conclusions: These results suggest that endot helin-A receptor antagonists may be useful in reducing ischemia/ reperfusion injury after heart transplanta tion by preservat ion of myocardial and endothelial function.
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