The coronary endothelial luminal membrane (CELM) glycocalyx has diverse molecules involved in blood flow signal transduction. Evidence suggests that some of these structures may be lectinic. To test this, we synthesized two monosaccharide polymers (Mon-Pols) made of Mannose (Man-Pol) or Galactose (Gal-Pol) covalently coupled to Dextran (70 kDa) and used them as lectin affinity probes. In situ intracoronary infusion of both polymers resulted in CELM-binding but only Man-Pol caused a reduction in flow-induced positive inotropism and dromotropism. To demonstrate that our lectinic probes could bind to CELM lectins, a representative CELM protein fraction was isolated via intracoronary infusion of a cationic silica colloid and either Mannose- or Galactose-binding lectins were purified from the CELM protein fraction using the corresponding Mon-Pol affinity chromatography resin. Resin-bound CELM proteins were eluted with the corresponding monosaccharide. 2D-SDS-PAGE (pH 4-7) revealed 9 Mannose- and approximately 100 Galactose-selective CELM lectins. In summary, the CELM glycocalyx contains Mannose- and Galactose-binding lectins that may be involved in translating coronary flow into a cardiac parenchymal response.