On the localization and mediation of the centrally induced hyperactive urinary bladder response to L-dopa in the rat

The hyperactive bladder response observed after central adrenergic stimulation with L-dopa, following enzymatic blockade of its peripheral metabolism, was studied in the rat. The bladder response was recorded by a cystometric procedure. The hyperactive bladder action thus produced was noted after transection of the CNS at the level of the superior colliculi but not when the transection was made caudal to the inferior colliculi. No effect was seen after transection of the cauda equina at L6, i.e. parasympathetic decentralisation of the bladder. It is concluded that the hyperactive bladder reaction seen after central adrenergic stimulation is produced in the mesencephalic-pontine region and mediated to the bladder via a central coupling to parasympathetic pathways.