URINARY-BLADDER DYSFUNCTION IN SPONTANEOUSLY DIABETIC CHINESE-HAMSTERS

Urinary bladder dysfunction was investigated in spontaneously diabetic Chinese hamsters of the Asahikawa colony (CHAD). The wet weight of th e urinary bladder was significantly increased in CHAD when compared wi th nondiabetic controls. In response to continuous infusion of physiol ogical saline into the bladder under anesthesia, regular micturition w as observed in controls. However, the threshold volume (i.e. the minim um volume at which rhythmic contraction appeared) was significantly in creased and the amplitude of bladder contractions during micturition w as decreased in CHAD aged 3-5 months (duration of diabetes, 0.6-2.2 mo nths), leading to incomplete micturition. The frequency of micturition was also increased. Overflow incontinence was observed in all CHAD ag ed 13-15 months (duration of diabetes, 10-14 months). Acetylcholineste rase staining and activity in the urinary bladder walls were both sign ificantly decreased in CHAD compared with controls. The in vitro incre ment of urinary bladder pressure caused by stimulation with bethanecho l was not different between CHAD and controls. These findings suggest that CHAD have urinary bladder dysfunction which is caused by autonomi c neuropathy and not by detrusor myopathy.