Coronary vasoactivity of adenosine covalently linked to polylysine

Abstract Adenosine was covalently linke to polylysine nonapeptide by reacting adenosine-5-carboxaldehyde with polylysine at pH 9.5, then reducing the Schiff base with NaBH 4 . The product (PLADO), which contained an average of two adenosine residues per molecule, did not penetrate cell membranes. When administered to two conscious instrumented dogs PLADO caused maximum coronary vasodilation at a concentration of 4 μM in coronary plasma water. This coronary vasodilatory effect was antagonized by aminophylline. Thus, after the administration of this methylxanthine coronary conductance increased by only 46% of maximum at a PLADO concentration of 6.9 μM. This result confirms earlier work using adenosine coupled to oxidized oligosaccharides that indicates the possibility of adenosine receptors on the surface of coronary myocytes.