BAMIFYLLINE SIMILAR TO THEOPHYLLINE AND CAFFEINE IS A COMPETITIVE INHIBITOR OF THE CYCLIC-NUCLEOTIDE PHOSPHODIESTERASE-V

Bamifylline was found to be a poor inhibitor of 3',5'-cyclic GMP phosp hodiesterase (PDE V) as other methylxanthines such as teophylline and caffeine, The IC50 was respectively 3.24, 2.98, 1.69 mM. Inhibition de creased at higher cGMP concentrations. Lineweaver-Burk plots were line ar or nearly linear, Differences in the actions of these inhibitors pr esumably reflect differences in the molecular requirements for effecti ve interaction at the catalytic site on phosphodiesterase.