Subsensitivity to ATP and some analogues in preparations of rat cauda epididymis and vas deferens after vasectomy.

1. The effects of ATP and some of its more stable analogues have been examined upon preparations of epididymal and prostatic halves of vasa deferentia and of cauda epididymides from rats that had undergone vasectomy by medial transection of the vas deferens. 2. After unilateral vasectomy, the potencies of ATP, beta, gamma-methylene ATP and 5'-adenylylimidodiphosphate (AppNHp) in tissues ipsilateral to the vasectomy were decreased compared to tissues from the contralateral unoperated side of the animal. 3. Tissues from bilaterally vasectomized rats were less responsive to ATP when compared to tissues taken from sham-operated rats. 4. Tissues taken from rats which had undergone vasovasostomies following unilateral vasectomy remained less responsive to these purines. 5. Responses of cauda epididymides and epididymal halves of vasa deferentia taken from unilaterally and bilaterally vasectomized rats to alpha, beta-methylene ATP usually did not differ from those of respective controls. 6. It is proposed that the subsensitivity which develops to ATP and some of its analogues on the epididymis and vas deferens following vasectomy may reflect increased breakdown, perhaps associated with changes in structural integrity of the tissues, rather than with the sympathetic denervation which is associated with vasectomy.