Unilateral denervation of the rat urinary bladder and reinnervation: a predominance for ipsilateral changes

Unilateral removal of the pelvic ganglion affected the bladder-half on the denervated side more profoundly than that on the non-denervated side. At an early stage (3-7 days) the former was heavier, had a lower choline acetyltransferase activity, developed less tension to nerve stimulation and, in course of time, became more sensitized to methacholine in vitro than the latter. At a late stage (30-60 days) the nerve-evoked contractile responses on the denervated side had increased, which was almost wholly attributed to the atropine-sensitive part of the contraction, but the recovery was not complete. On the non-denervated side the nerve-evoked responses were not significantly changed. It was calculated that in the normally innervated bladders 25-30% of the cholinergic nerves of each half were of contralateral origin. The figure was lower (18%) for the nerves mediating the atropine-resistant response.