Effects of adenosine 5'-triphosphate, adenosine and acetylcholine in urinary bladder and colon muscles from streptozotocin diabetic rats.

Bladder dysfunction and gastrointestinal disorders are common complications of diabetes mellitus and are attributed in part to peripheral neuropathy. Little is known of the mechanisms responsible for the bladder dysfunction and abnormality of the gastrointestinal tract. The effects of experimental diabetes on responses to adenosine, adenosine 5'-triphosphate (ATP) and acetylcholine (ACh) in rat bladder and colon were investigated 1 week and 8 weeks after i.v. injection of streptozotocin. Bladders from 8 week diabetic rats, but not from 1 week, were significantly larger than those from age matched controls. Relaxant and contractile responses of strips obtained from bladder body to these agonists were altered by diabetes. Relaxant responses to adenosine and ATP were also enhanced by diabetes. While maximum response and sensitivity to ATP relaxant effect were equivalent in 1 and 8 week diabetic rats as compared to age matched controls, both maximum responses to relaxant effect of adenosine and to contractile effect of ACh were reduced in colon preparations obtained from 8 week, but not from 1 week diabetic animals. The results suggest that changes in urinary bladder and colon smooth muscle function occur in diabetic rats and may contribute to the bladder dysfunction and colonic disorders seen in diabetes mellitus.