The effect of noradrenaline on the contractile response of the urinary bladder. An in vitro study in man and cat.

In this study, bladder muscle strips from the detrusor of man and cat were used to evaluate the modulating effects of adrenergic agonist and antagonists on the field stimulation induced contractile response. Noradrenaline (NA) inhibited and phentolamine enhanced the contraction in a dose-dependent manner. Propranolol did not influence the field stimulation response. When a study of the combined effect of adrenergic drug influence was performed, the NA-induced inhibition was partly reversed by propranolol but a further increase of the contractile response compared to the control was seen, when phentolamine was added. No species differences were found. The conclusion drawn from these results is, that the inhibiting effect of NA on the contractile response is mediated via alpha- and beta-adrenergic receptors. The former could be located on the short parasympathetic intramural neurons while the latter probably are located on muscle cells.