Effect of decentralization and partial outflow obstruction on cholinergic receptors in urinary bladder of rabbit

In this study we have examined the cholinergic receptor density on the detrusor smooth muscle from rabbits with decentralized autonomous bladders and animals with partial outlet obstructions using (3H) quinuclidinyl benzilate ([3H] QNB). Decentralized spinal bladders were obtained from rabbits made paraplegic by a twenty-minute ischemic lesion to the lumbar and sacral spinal cord. Bladder tissues from these rabbits were studied from one, two, five, and nine-day intervals after the ischemic lesion. The affinity of the muscarinic binding sites for (3H) QNB was virtually unchanged at any of the time intervals, while the total Bmax was significantly reduced at one and two days but recovered to normal levels by the fifth and ninth day after the ischemic lesion, provided the bladder had been effectively manually emptied on a regular basis. In a parallel study animals with a partial outlet obstruction or spinal animals with marked bladder distention at the time of sacrifice showed that the cholinergic receptor density was significantly reduced.