Bamifylline Similar to Theophylline and Caffeine is a Competitive Inhibitor of the Cyclic Nucleotide Phosphodiesterase V

Abstract

Bamifylline was found to be a poor inhibitor of 3′,5′-cyclic GMP phosphodiesterase (PDE V) as other methylxanthines such as teophylline and caffeine. The IC₅₀ was respectively 3.24, 2.91, 1.69 mM. Inhibition decreased at higher cGMP concentrations. Lineweaver-Burk plots were linear or nearly linear. Differences in the actions of these inhibitors presumably reflect differences in the molecular requirements for effective interaction at the catalytic site on phosphodiesterase.