Acetylcholine release from urinary bladder smooth muscles of non-insulin-dependent diabetic rats.
BACKGROUND
To investigate the mechanism of voiding dysfunction in non-insulin-dependent diabetes mellitus, we attempted to measure the acetylcholine (ACh) release using an in vivo microdialysis technique and measuring the detrusor pressure after electrical field stimulation (EFS) of the pelvic nerve.


METHODS
Eight- and 32-week-old female Goto-Kakizaki (GK) rats (non-insulin-dependent diabetes mellitus model) and age-matched female Wistar rats (controls) were used in this study. The pelvic nerve was exposed on a bipolar platinum electrode to EFS, and a cannula was inserted into the bladder to measure the detrusor pressure. The microdialysis probe was inserted into the bladder wall and was connected to a microinfusion syringe pump. Dialysate was constantly perfused, collected in a microtube, and then injected into the ACh assay system. Histological examinations were performed by staining with hematoxylin and eosin and S-100 immunohistochemical staining in bladder preparations of both GK and control rats.


RESULTS
In 8-week-old rats, both detrusor pressures and amounts of ACh release of GK rats were not significantly different from those of control rats. In 32-week-old rats, both detrusor pressures and ACh releases were only significantly increased at 5 and 10 Hz of EFS. In the histological study, the number of nerve fibers or bundles of 32-week-old GK rats was significantly decreased as compared with control rats.


CONCLUSIONS
The present data suggest that the decrease in EFS-induced ACh release in GK rats, which may be caused by the decreased number of nerve fibers, may contribute to the decrease in bladder contractions.
Miyamae
Koichi
K
Department of Urology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
Yoshida
Masaki
M
Inadome
Akito
A
Murakami
Shigetaka
S
Otani
Masayuki
M
Iwashita
Hitoshi
H
Masunaga
Koichi
K
Ueda
Shoichi
S
D000109:Acetylcholine / Q000378:metabolism*; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism* / Q000503:physiopathology; D004558:Electric Stimulation; D005260:Female; D009130:Muscle, Smooth / Q000378:metabolism* / Q000503:physiopathology; D011312:Pressure; D051381:Rats; D017208:Rats, Wistar; D001743:Urinary Bladder / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology
D000109:Acetylcholine