Species differences in cAMP production and contractile response induced by β‐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.