The role of pubococcygeus muscle in urinary continence in the male rat.

The role of the male rat pubococcygeus muscle (Pcm) in the micturition reflex was analyzed. Anatomical features of Pcm, electrical stimulation of its nerve, electrical recording and stimulation of the muscle and cystometrograms were carried out. Results showed that Pcm has fibers attached to the ventrolateral part of the external urethral sphincter, and that its activity contributes to hold the tail in the midline. Pcm shows activity during fluid expulsion in cystometrograms and spontaneous micturitions. This activity produced reflex inhibition of detrusor contraction and was not the cause of intravesical high frequency oscillations. Thus, it is proposed that Pcm activity produces the discharge of its afferents which in turn activates a spinal reflex to promote continence.