Decreased expression of G protein-coupled receptor kinases in the detrusor smooth muscle of human urinary bladder with outlet obstruction.
OBJECTIVE
We examine the expression of mRNA of G protein-coupled receptor kinase (GRK) subtypes and muscarinic acetylcholine receptor (M) subtypes in the detrusor smooth muscle of the human urinary bladder. Furthermore, we confirm the presence and the localization of GRK proteins in the detrusor smooth muscle of the obstructed bladder in comparison with the control bladder.


METHODS
Detrusor smooth muscle tissues of the human urinary bladder were obtained from 12 male patients; 6 patients did not have bladder outlet obstruction, and the other 6 patients had bladder outlet obstruction. Portions of the dome or anterior wall of the urinary bladder were used for the present study. Reverse transcription/polymerase chain reaction for GRK2, M2 and M3 was performed using total RNA extracted from human urinary bladder detrusor. Antibodies to GRK2, GRK3 and GRK4 were used to confirm the presence of the protein product in the human urinary bladder using immunohistochemical staining and the western blotting technique.


RESULTS
All complementary DNA (cDNA) transcribed from three different mRNA (M2, M3 and GRK2) were successfully amplified and size-fractionated. The expression of GRK2 protein was strong in the human bladder detrusor, but was significantly weakened by western blotting in obstructed bladder in comparison with control bladder.


CONCLUSIONS
Failure in desensitization mechanisms of muscarinic acetylcholine receptors might be related to storage symptom elicited by overactivity in obstructed bladder with benign prostatic hyperplasia.
Furuya
Yasuhisa
Y
Department of Urology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Yamanashi, Japan. yfuruya@res.yamanashi-med.ac.jp
Araki
Isao
I
Kamiyama
Manabu
M
Zakoji
Hidenori
H
Takihana
Yoshio
Y
Takeda
Masayuki
M
D015153:Blotting, Western; D054769:G-Protein-Coupled Receptor Kinase 2; D054770:G-Protein-Coupled Receptor Kinase 3; D054771:G-Protein-Coupled Receptor Kinase 4; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D009130:Muscle, Smooth / Q000166:cytology / Q000201:enzymology*; D011470:Prostatic Hyperplasia / Q000201:enzymology* / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043585:Receptor, Muscarinic M2 / Q000235:genetics / Q000378:metabolism; D043587:Receptor, Muscarinic M3 / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D001743:Urinary Bladder / Q000166:cytology / Q000201:enzymology*; D001748:Urinary Bladder Neck Obstruction / Q000201:enzymology* / Q000473:pathology; D051552:beta-Adrenergic Receptor Kinases / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D043585:Receptor, Muscarinic M2; D043587:Receptor, Muscarinic M3; D017346:Protein Serine-Threonine Kinases; D054770:G-Protein-Coupled Receptor Kinase 3; C496567:GRK2 protein, human; C517848:GRK3 protein, human; D051552:beta-Adrenergic Receptor Kinases; D054769:G-Protein-Coupled Receptor Kinase 2; D054771:G-Protein-Coupled Receptor Kinase 4; C517855:GRK4 protein, human