adenosine-5--o-(3-thiotriphosphate) and 1-5-difluoro-2-4-dinitrobenzene

1. The effects of some possible inhibitors of ectonucleotidases on the breakdown of extracellular ATP by strips of guinea-pig urinary bladder were investigated. 2. Suramin and ethacrynic acid (10 mM) both inhibited ATP breakdown significantly, and difluorodinitrobenzene (10 mM) inhibited it slightly whereas N-ethylmaleimide, adenosine 5'-(gamma-thiotriphosphate) (ATP-gamma-S) and reactive blue-2 (10 mM) were without effect. 3. The inhibitory effects of suramin on ATP breakdown were non-competitive. 4. Ethacrynic acid (1 mM) irreversibly inhibited contractions of the guinea-pig bladder induced by ATP, substance P, histamine, non-adrenergic, non-cholinergic nerve stimulation or KCl, whereas suramin (100 microM) had no inhibitory effect. 5. The results suggest that suramin might provide a starting point for the design of selective inhibitors of ectonucleotidases.

Topics: Adenosine Triphosphate; Animals; Dinitrofluorobenzene; Electric Stimulation; Ethacrynic Acid; Ethylmaleimide; Female; Guinea Pigs; Half-Life; In Vitro Techniques; Kinetics; Male; Muscle Contraction; Muscle, Smooth; Nucleotidases; Potassium Chloride; Suramin; Urinary Bladder