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The role of the rhabdosphincter in female rat voiding

Streng, Tomi LU ; Santti, R; Andersson, Karl-Erik LU and Talo, A (2004) In BJU International1999-01-01+01:00 94(1). p.138-142
Abstract
Objectves To obtain information on the mechanisms of female rat micturition using a model in which pressure was measured in the bladder and distal part of the urethra corresponding to the location of the rhabdosphincter, providing information on the role of the sphincter in opening and closing the urethral lumen. Materials and Methods A micturition reflex was induced in adult anaesthetized (chloral hydrate and urethane) female rats by filling the bladder with saline. Bladder pressure (BP), urethral pressure (UP), electromyography (EMG) of the middle part of the rhabdosphincter, and urinary flow rate in the distal urethra were simultaneously recorded. Results There were four phases of the micturition contraction, the second characterized by... (More)
Objectves To obtain information on the mechanisms of female rat micturition using a model in which pressure was measured in the bladder and distal part of the urethra corresponding to the location of the rhabdosphincter, providing information on the role of the sphincter in opening and closing the urethral lumen. Materials and Methods A micturition reflex was induced in adult anaesthetized (chloral hydrate and urethane) female rats by filling the bladder with saline. Bladder pressure (BP), urethral pressure (UP), electromyography (EMG) of the middle part of the rhabdosphincter, and urinary flow rate in the distal urethra were simultaneously recorded. Results There were four phases of the micturition contraction, the second characterized by intraluminal pressure high-frequency oscillations (IPHFOs) of BP. When a non-oscillatory micturition contraction started, the BP increased and exceeded UP for the rest of the micturition contraction. Even though the BP increased during this first phase, the urethral lumen stayed closed. Its opening was indicated by a simultaneous decrease in BP and increase of UP as the fluid flowed from the bladder to the urethra. When the rhabdosphincter closed, as indicated by an EMG-burst of the muscle, the UP declined, bladder pressure increased and the flow ceased. Because of momentary contractions of the rhabdosphincter, the UP and urine flow rate had the same periodicity as the IPHFOs of BP. Conclusions The simultaneous recording of the BP, UP, EMG of the rhabdosphincter and urinary flow rate showed the sequence of events during micturition. The rhabdosphincter acts as an 'on-off' switch, causing interruptions in the urinary flow rate. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
flow rate, urinary, rhabdosphincter EMG, urethral pressure, voiding, female rat
in
BJU International1999-01-01+01:00
volume
94
issue
1
pages
138 - 142
publisher
Blackwell Science Ltd
external identifiers
  • wos:000222290100032
  • pmid:15217449
  • scopus:3342947903
ISSN
1464-4096
DOI
10.1111/j.1464-4096.2004.04875.x
language
English
LU publication?
yes
id
8e36f096-d503-4c3b-ace7-28869ee25b63 (old id 273593)
date added to LUP
2007-11-02 10:03:50
date last changed
2017-11-05 03:44:07
@article{8e36f096-d503-4c3b-ace7-28869ee25b63,
  abstract     = {Objectves To obtain information on the mechanisms of female rat micturition using a model in which pressure was measured in the bladder and distal part of the urethra corresponding to the location of the rhabdosphincter, providing information on the role of the sphincter in opening and closing the urethral lumen. Materials and Methods A micturition reflex was induced in adult anaesthetized (chloral hydrate and urethane) female rats by filling the bladder with saline. Bladder pressure (BP), urethral pressure (UP), electromyography (EMG) of the middle part of the rhabdosphincter, and urinary flow rate in the distal urethra were simultaneously recorded. Results There were four phases of the micturition contraction, the second characterized by intraluminal pressure high-frequency oscillations (IPHFOs) of BP. When a non-oscillatory micturition contraction started, the BP increased and exceeded UP for the rest of the micturition contraction. Even though the BP increased during this first phase, the urethral lumen stayed closed. Its opening was indicated by a simultaneous decrease in BP and increase of UP as the fluid flowed from the bladder to the urethra. When the rhabdosphincter closed, as indicated by an EMG-burst of the muscle, the UP declined, bladder pressure increased and the flow ceased. Because of momentary contractions of the rhabdosphincter, the UP and urine flow rate had the same periodicity as the IPHFOs of BP. Conclusions The simultaneous recording of the BP, UP, EMG of the rhabdosphincter and urinary flow rate showed the sequence of events during micturition. The rhabdosphincter acts as an 'on-off' switch, causing interruptions in the urinary flow rate.},
  author       = {Streng, Tomi and Santti, R and Andersson, Karl-Erik and Talo, A},
  issn         = {1464-4096},
  keyword      = {flow rate,urinary,rhabdosphincter EMG,urethral pressure,voiding,female rat},
  language     = {eng},
  number       = {1},
  pages        = {138--142},
  publisher    = {Blackwell Science Ltd},
  series       = {BJU International1999-01-01+01:00},
  title        = {The role of the rhabdosphincter in female rat voiding},
  url          = {http://dx.doi.org/10.1111/j.1464-4096.2004.04875.x},
  volume       = {94},
  year         = {2004},
}