ABSTRACT
Purines have widespread and specific extracellular ignaling 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 KCl and Ach was investigated invitro. Preperations were prepreated with adenosine or ATP be for agonist exposure. It was found that adenosine inhibited K- induced contracture and enhanced Ach- induced contracture. These actions were blocked by Pi antagonist theophylline. The results also show that ATP potentiated both KCl and Ach induced contracture. Theses actions antagonized by P[2] receptor antagonist Quinidine. These results suggest that blader smoth muscle may have A[j], A[2] and P[2x] receptors