Electromyographic and pressure studies in the canine bladder.

The dog is unable to void until funnelling of the bladder neck occurs, even when the bladder is stressed with a large volume and with parasympathomimetic drugs. Nil or very little pressure rise occurs just prior to micturition. Well-coordinated voiding is associated with simultaneous electrical activity in either the upper urethra and bladder neck or these two areas plus the fundus, with predominance of electrical activity (frequency and amplitude) in the bladder neck in both circumstances. In cooordinate electrical activity is seen in bladder fundus, bladder neck, and upper urethra with incoordinate voiding.