Changes in the contractile activity of the male genital tract as a consequence of vasectomy

The contractile activity of the cauda epididymidis and vas deferens was registered in the rat under a video camera at intervals up to 180 days after vasectomy. A rhythmic peristaltic activity was detected as early as 24 hours after operation, specially in the distal cauda epididymidis. The contractions increased progressively during the first 30 days after vasectomies. Thereafter, the activity remained stabilized as far as 180 days following the surgery. The contractions were more frequent in the genital tracts without granulomas than in those with this complication. When the ductus exhibited an excessive distention their muscle walls did not show any contractility, which was not recovered even when a partial incision was made in the vas deferens to diminish the tube dilatation. Since a normal pattern of sperm transport would be necessary to achieve sperm maturation, it could be speculated that persistence of infertility after vasovasostomies in human could be related with a loss of an adequate ductal activity.