RESUMEN
Purines have widespread and specific extracellular signalling actions in the regulation of a variety of functions in many tissues of both invertebrates and vertebrates. The effect of some adenosine compound on sheep bladder smooth muscle contraction induced by KCI and ACh was investigated invitro. Preparations were prepreated with adenosine or ATP befor agonist exposure. It was found that adenosine inhibited K- induced contracture and enhanced Ach-induced contracture. These actions were blocked by P[1] antagonist theophylline. The results also show that ATP potentiated both KCI and ACh induced contracture. Theses actions antagonized by P[2] receptor antagonist Quinidine. These results suggest that blader smoth muscle may have A[1], A[2] and P[2x] receptors