PMID- 22520450
OWN - NLM
STAT- MEDLINE
DCOM- 20121207
LR  - 20121001
IS  - 1464-410X (Electronic)
IS  - 1464-4096 (Linking)
VI  - 110
IP  - 8 Pt B
DP  - 2012 Oct
TI  - Large-conductance calcium-activated potassium channel activity, as determined by 
      whole-cell patch clamp recording, is decreased in urinary bladder smooth muscle 
      cells from male rats with partial urethral obstruction.
PG  - E402-8
LID - 10.1111/j.1464-410X.2012.11137.x [doi]
AB  - OBJECTIVES: To examine the effect of partial urethral obstruction (PUO) on 
      bladder smooth muscle outward potassium current and the contribution of the 
      large-conductance calcium-activated potassium (Maxi-K, BKCa) channel to this 
      activity in smooth muscle cells isolated from bladders of sham-operated and PUO 
      male rats using whole-cell patch clamp recording techniques. To determine the 
      effect of PUO on the expression of the Maxi-K channel alpha and beta1 subunits and in 
      vitro detrusor contractility. MATERIALS AND METHODS: Twenty adult male 
      Sprague-Dawley rats were divided equally into two groups and subjected to 
      surgical ligation of the urethra (PUO) or sham surgery (SHAM). After 2 weeks, the 
      detrusors from PUO and SHAM rats were used for molecular analyses (mRNA and 
      protein quantification of Maxi-K subunits) or organ bath contractility studies, 
      or myocytes were isolated for conventional whole-cell patch clamp analyses. 
      RESULTS: PUO increased bladder mass 2.5-fold and detrusor strips exhibited a more 
      tonic-type contraction and increased contractility compared with controls (SHAM). 
      Iberiotoxin (300 nM) sensitive Maxi-K channel current comprised about 40% of the 
      outward whole-cell current in SHAM bladders but only about 8% in PUO bladders. 
      Expression of the alpha subunit of the Maxi-K channel was significantly decreased 
      ~40% while the expression of the beta1 subunit was increased ~2-fold at the mRNA 
      level. The increase in beta1 expression was confirmed by Western blotting. 
      CONCLUSIONS: Our findings show that obstruction of the rat bladder is associated 
      with decreased Maxi-K channel activity of bladder smooth muscle cells, determined 
      via direct current measurement. Increased expression of the beta1 subunit points to 
      a compensatory reaction to decreased Maxi-K channel activity. Maxi-K channel 
      openers or gene therapy may therefore provide therapeutic benefit for the 
      overactive bladder.
CI  - (c) 2012 BJU INTERNATIONAL.
FAU - Aydin, Memduh
AU  - Aydin M
AD  - Department of Urology, Albert Einstein College of Medicine, New York, New York, 
      USA.
FAU - Wang, Hong Zhan
AU  - Wang HZ
FAU - Zhang, Xinhua
AU  - Zhang X
FAU - Chua, Rowena
AU  - Chua R
FAU - Downing, Keith
AU  - Downing K
FAU - Melman, Arnold
AU  - Melman A
FAU - DiSanto, Michael E
AU  - DiSanto ME
LA  - eng
GR  - R01 DK077116/DK/NIDDK NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
DEP - 20120423
PL  - England
TA  - BJU Int
JT  - BJU international
JID - 100886721
RN  - 0 (Large-Conductance Calcium-Activated Potassium Channels)
SB  - IM
MH  - Animals
MH  - Cells, Cultured
MH  - Large-Conductance Calcium-Activated Potassium Channels/*physiology
MH  - Male
MH  - Myocytes, Smooth Muscle/*physiology
MH  - Patch-Clamp Techniques
MH  - Rats
MH  - Rats, Sprague-Dawley
MH  - Urethral Obstruction/*physiopathology
MH  - Urinary Bladder/*physiopathology
EDAT- 2012/04/24 06:00
MHDA- 2012/12/12 06:00
CRDT- 2012/04/24 06:00
PHST- 2012/04/24 06:00 [entrez]
PHST- 2012/04/24 06:00 [pubmed]
PHST- 2012/12/12 06:00 [medline]
AID - 10.1111/j.1464-410X.2012.11137.x [doi]
PST - ppublish
SO  - BJU Int. 2012 Oct;110(8 Pt B):E402-8. doi: 10.1111/j.1464-410X.2012.11137.x. Epub 
      2012 Apr 23.