Inverse agonist of Mas G-protein signaling (IC50 values 186 and 348 nM in human and rat inositol phosphatase (IP) Gq coupling assays respectively). AR 244555 caused a dose-dependent inhibition of inositol 1,4,5-trisphosphate accumulation in AdMas-infected cells, and attenuated the sarcomeric organization and cell enlargement observed in Mas overexpressing myocytes.AR 244555 caused a modest but significant increase in coronary flow in rat hearts witout causing arrhythmias, and provides protection from ischemia-reperfusion injury if administered either before ischemia or immediately before reperfusion.