Nervous Control of Urinary Bladder in Cats: IV. Effects of autonomic blocking agents on responses to peripheral nerve stimulation

E dvardsen , P. Nervous control of urinary bladder in cats. IV. Effects of autonomic blocking agents on responses to peripheral nerve. stimulation . Acta physiol. scand. 1968. 72 . 231–247. The bladder response to electrical stimulation of the parasymipathetic and sympathetic. nerves was recorded in anesthetized cats. Stimulation of the pelvic nerves caused a sustained bladder contraction. This response was not changed significantly by blockade with atropine at 5 cps stimulation, while at 30 cps only an initial contraction was obtained. It was abolished with hexamethomium , whereas it remained unchanged after guanethidine, propranolol and dibenzy‐linc . There was no evidence to suggest the presence of inhibitory fibres. Stimulation of the hypogastric nerves gave rise to an initial contraction followed by relaxation. On continuous stimulation the slope of the pressure volume curve was flattened in proportion to the strength of stimulation. However. during the relation phase of the detrusor muscle, the bladder outlet responded by contraction. The sympathetic response was blocked by guanethidine, but this, in small doses, augmented the contraction phase. Propranolol increased the contraction phase, and in addition converted the relaxation to contraction. The contraction response could be blocked selectively by administration of dibenzyline . It is suggested that adrenergic alpha‐receptors are present both at the bladder outlet, and in the detrusor muscle as well. but that in the latter case their presence is masked by the inhibitory beta‐receptors.