Reappraisal of the sympathetic role in the sphincteric urethra. Denervation supersensitivity of the urethra of the chronic neurogenic bladder to alpha-adrenergic drugs.

The response of urethral pressure to administration of an alpha-stimulant was compared between a group of eight patients with chronic neurogenic bladders as evidenced by positive denervation supersensitivity to parasympathomimetic bethanechol chloride and a group of ten control patients. A supersensitive response to administration of an alpha-stimulant with a rise of maximum urethral pressure, 10 mm Hg or more above the control urethral pressure, was uniformly observed in the urethra of patients with chronically denervated bladders. Our results appear to add pharmacologic evidence of alpha-adrenergic predominance over the parasympathetic in the urethra which is believed to be innervated dually in the recently envolving new concept.