[Evidence of occurrence of gap junctions in stable nonobstructed human bladder].
OBJECTIVE
To investigate the occurrence of gap junctions and the gap junction forming protein connexin (Cx) in normal human detrusor.


METHODS
Specimens of detrusor smooth muscle were obtained from 6 patients with localized bladder tumors during radical cystectomy. Transmission electron microscopy and freeze fracture microscopy were used to observe the microstructure of the detrusor smooth muscle. Reverse transcription polymerase chain reaction (RT-PCR) and fluorescence immunohistochemistry was used to detect the expression of Cx in the detrusor smooth muscle.


RESULTS
Ultrastructural and freeze fracture studies showed gap junctions in the detrusor smooth muscle cells. However, these gap junctions appeared to be small and irregularly shaped. RT-PCR amplified 2 fragments with the lengths of 300 bp and 200 bp, and sequencing showed that they were identical with the Cx45 already published. Fluorescence immunohistochemistry showed the existence of immunological signal of Cx45 in most of the detrusor smooth muscles.


CONCLUSIONS
The smooth muscle cells of stable human detrusor are electrically coupled through gap junctions.
Wang
Xiang
X
Department of Urology, China-Japan Friendship Hospital, Beijing 100029, China. wangxiang-uro@hotmail.com
Caroline
Maake
M
Hubert
John
J
D000368:Aged; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D008875:Middle Aged; D009130:Muscle, Smooth / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D001743:Urinary Bladder / Q000378:metabolism* / Q000648:ultrastructure; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology