Noradrenergic Reinnervation of the Rat Vas Deferens After Vasovasostomy Following Vasectomy

Abstract

1. Anastomosis (vasovasostomy) of epididymal and prostatic halves of vasa deferentia was carried out in rats in which unilateral or bilateral medial transection (vasectomy) had been performed 4 weeks previously. 2. Noradrenaline levels in epididymal halves of vasa deferentia, 8 weeks after anastomosis with prostatic halves, were approximately 40% of those in epididymal halves of contralateral, unoperated vasa deferentia. Catecholamine fluorescence was partially restored after anastomosis. 3. Responses of epididymal halves of transected vasa deferentia to electrical field stimulation (1 ms, 60 V, 10 pulses at 0.01-50 Hz) were partially restored 8 and 15 weeks after anastomosis. 4. Noradrenaline was equipotent in causing contraction of epididymal halves of unoperated and anastomosed vasa deferentia at 8 and 15 weeks after vasovasostomy. The ability of nisoxetine (0.1 mumol/l) to potentiate the effects of noradrenaline was partially restored by vas deferens repair. 5. Noradrenaline levels and neurotransmission in prostatic halves of vasa deferentia were relatively unaffected by vasectomy and subsequent vasovasostomy. 6. Fertility was restored 4-8 weeks after bilateral anastomosis performed in a group of eight rats 4 weeks after bilateral vasectomy. 7. These observations show that in the rat the noradrenergic denervation of the epididymal segment of the vas deferens after medial transection is partially reversible by anastomosis 4 weeks later, and that full noradrenergic reinnervation of the organ is not essential for the return of fertility after vasectomy and vasovasostomy in this species.

Prolonged supersensitivity to noradrenaline of smooth muscle of the epididymal half of the rat vas deferens denervated by vasectomy

“…In prostatic halves of transected vasa deferentia, twitch inhibition by noradrenaline was enhanced by nisoxetine to an extent similar to that in preparations of prostatic halves from contralateral unoperated vasa deferentia, indicating that in this segment there is no loss of the uptake capacity of postganglionic noradrenergic nerves, in which connections with preganglionic fibres are preserved. Indeed, in a separate group ofexperiments with unilaterally and bilaterally vasectomized rats, we have found that both the denervation, and the denervation supersensitivity, of the epididy-ma1 segment after vasectomy, can be reversed by anastomosis of the divided segments (DeGaris 1987). Uptake capacity, as determined by examination of the effects of nisoxetine upon responses to noradrenaline of epididymal segments from vasovasostomized animals, is also partially regained.…”

“…Medial transection in vivo of the epididymal segment of the rat vas deferens leads to a progressive decline in catecholamine levels (Norberg et al, 1967), and to a loss of response of isolated preparations to transmural stimulation, for at least 6 months after surgery (DeGaris & Pennefather, 1986a, b;1987). No comparable changes occur in the prostatic half of the tissue in which the normal relationship between the pre-and postganglionic nerve fibres is preserved (DeGaris & Pennefather, 1986a).…”

“…Moreover, there was minimal disturbance of the blood supply to the denervated segment, and no tissue atrophy. In the 6 month period after vasectomy, there is negligible reinnervation of the epididymal segment (DeGaris & Pennefather, 1987). Catecholamine levels and responses to field stimulation in the prostatic halves of the operated vas deferens remain unaffected.…”

Subsensitivity to Atp and Some Analogues in Preparations of Rat Cauda Epididymis and Vas Deferens After Vasectomy

“…Supersensitivity to noradrenaline does not occur in the prostatic segment of the operated vas deferens, which is not denervated by the surgical procedure. The supersensitivity associated with vasectomy-induced denervation of epididymal segments of the vas deferens has been shown to be partly reversed following partial re-innervation of these segments after vasovasostomy (DeGaris & Pennefather 1987b).…”