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 complica tions of diabetes mellitus and are attributed in part to peripheral ne uropathy. Little is known of the mechanisms responsible for the bladde r dysfunction and abnormality of the gastrointestinal tract. The effec ts of experimental diabetes on responses to adenosine, adenosine 5'-tr iphosphate (ATP) and acetylcholine (ACh) in rat bladder and colon were investigated 1 week and 8 weeks after i.v. injection of streptozotoci n. Bladders from 8 week diabetic rats, but not from 1 week, were signi ficantly larger than those from age matched controls, Relaxant and con tractile responses of strips obtained from bladder body to these agoni sts 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 relaxan t 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 colo n smooth muscle function occur in diabetic rats and may contribute to the bladder dysfunction and colonic disorders seen in diabetes mellitu s.