Modulation of Excitatory Perineal Reflexes and Sacral Striated Sphincter Motoneurons During Micturition in the Cat

Abstract During micturition, activation of the sacral parasympathetic outflow responsible for contracting the bladder occurs at the same time as a decrease in activity in the striated urethral sphincter muscle. This reciprocal pattern allows for the efficient emptying of the bladder in humans and in the cat (for review see deGroat, 1990; however, see Kruse et al., 1993 for differences in the rat). Failure of the mechanisms responsible for suppressing sphincter activity during micturition is a hallmark of many suprasacralneural lesions and is referred to as bladder-sphincter dyssynergia (for discussion see Rudy et al., 1988; Sethiet al., 1989). It is this inappropriate sphincter activity that often leads to deterioration of upper urinary tract function and thus represents a major clinical problem for such patients.