Glucagon-like peptide-1 (GlP-1) and its receptor (GlP-1r) exert cardioprotective effects after myocardial ischemia and reperfusion (Mi/r) in animal models and human clinical trials. receptor imaging with positron emis- sion tomography (PeT) provides a non-invasive method for monitoring GlP-1r expression. in the present study, a fluorine-18-labeled aluminum fluoride exendin-4 analog [18 F-alF conjugated with 1,4,7-triazacyclononanetriacetic acid (noTa)-maleimide (Mal)-cys40 -exendin-4] was synthesized and evaluated in a rat Mi/r model for GlP-1r imaging. noTa-Mal-cys40 -exendin-4 was synthe- sized by coupling cys40 -exendin-4 with noTa-Mal. noTa-Mal-cys40 -exendin-4 was then conjugated with 18F-alF to obtain 18 F-alF-noTa-Mal-cys40 -exendin-4. The yield of 18 F-alF-noTa-Mal-cys40 -exendin-4 was 18.5±3.4% (not decay corrected). The process was completed within ~30 min. In rat MI/R models, the tracer exhibited specific binding to GlP-1r and an appropriate signal-to-noise ratio. at 8 h post-Mi/r, tracer uptake reached its peak [0.35±0.053% of injected dose (%id)/g; n=6] in ischemic myocardium. localized tracer uptake decreased 1 day (0.20±0.032 %id/g; n=6) and 3 days (0.16±0.017 %id/g; n=6) post-Mi/r compared with 8 h post-Mi/r, but still remained higher compared with sham-operated groups (0.06±0.012 %id/g; n=6). Pre-injected Correspondence to: dr Haokao Gao, department of cardiology, Xijing Hospital, The Fourth Military Medical university, 169 changlexi road, Xi'an, Shaanxi 710032, P.r. china e-mail: hk_gao@163.com Professor Haichang Wang, department of cardiology, Tangdu Hospital, The Fourth Military Medical university, 1 Xinsi road, Xi'an, Shaanxi 710038, P.r. china e-mail: wanghc@fmmu.edu.cn Key words: glucagon-like peptide-1 receptor, exendin-4, positron emission tomography imaging, myocardial reperfusion injury, fluorine-18 unlabeled exendin-4 effectively blocked tracer accumulation (0.09±0.041 %id/g; n=6). in conclusion, 18F-alF-noTa-Ma l-cys40 -exendin-4 demonstrated favorable characteristics for GlP-1r imaging following Mi/r. PeT imaging using 18 F-al F-noTa-Mal-cys40 -exendin-4 in rodent hearts after Mi/r revealed a dynamic pattern of GlP-1r upregulation.