Species differences in cAMP production and contractile response induced by beta-adrenoceptor subtypes in urinary bladder smooth muscle.

The contractile activity of urinary bladder smooth muscle has been shown to be inhibited by beta-adrenoceptor agonists. beta-Adrenoceptor subtypes in the rabbit, canine, and human urinary bladder smooth muscles were studied by measuring changes in contractile forces and in intracellular cAMP concentrations on administration of beta-adrenoceptor agonists. In the rabbit bladder, only beta 2-receptors may have functional roles in the detrusor muscle, while both beta 1- and beta 2-receptors may have functional roles in the detrusor muscles of the canine bladder. Only beta 2-receptors may have functional roles in the human detrusor muscles, similar to the rabbit detrusor muscles. Thus, species differences may exist in beta-adrenoceptor subtypes in smooth muscles of urinary bladder.