Ablation of the inferior mesenteric plexus in the rat: alteration of sperm storage in the epididymis and vas deferens.

The involvement of the sympathetic nervous system in the transport and storage of spermatozoa in the male reproductive tract was examined by surgically ablating the inferior mesenteric plexus (IMP). One to eight weeks after ablation of the IMP, epididymal weight and the total number of spermatozoa present in the cauda epididymidis were significantly greater in IMP-ablated rats than in sham-operated rats. By contrast, the number of spermatozoa present in the initial segment of the vas deferens was significantly greater than in sham operated controls one week after IMP ablation but returned to control levels at two, four, six and eight weeks. Throughout the experiment, no differences were observed between IMP-ablated and control rats in the percentage of motile cauda epididymal spermatozoa, testicular weight, testicular sperm number or serum testosterone. These data demonstrate that the sympathetic nervous system differentially regulates sperm transport and storage in the male reproductive tract and suggest that the IMP may influence the epididymal maturation of spermatozoa.