Human vasal changes after vasectomy: in vitro studies.
UNLABELLED: Failure to impregnate, after successful vasovasostomy, has been attributed to immunologic, testicular, and epididymal factors. OBJECTIVES: To study the effect of vasectomy on human vas innervation and vesicoelastic properties. METHODS: Vas rings were obtained from 8 healthy males during vasectomy as controls and compared to those of 3 vasovasostomy patients. The active and passive properties were determined and the cumulative blocking effects of phenoxybenzamine, propranolol, atropine and tetrodotoxin were studied. RESULTS: There was significantly higher rigidity in the vasovasostomy group as compared to the control group but there were similar active forces between the two groups up to 100-120% of stretch. In the control group, phenoxybenzamine blocked 33.3%, propranolol blocked 15.8%, and atropine blocked 36.5% but tetrodotoxin had no further effect. In the vasovasostomy group, phenoxybenzamine blocked 33.3% (similar to control), propranolol blocked 2%, atropine blocked 11.7% and tetrodotoxin blocked 37.1%. CONCLUSIONS: In vasovasostomy group there was increased rigidity without reduction of the active force. There were also decreased cholinergic and possible existence of nonadrenergic noncholinergic neurotransmitters.