A1 Refereed original research article in a scientific journal
Possible action of the proximal rhabdosphincter muscle in micturition of the adult male rat
Authors: Streng T, Santti R, Talo A
Publisher: WILEY-LISS
Publication year: 2001
Journal:: Neurourology and Urodynamics
Journal name in source: NEUROUROLOGY AND URODYNAMICS
Journal acronym: NEUROUROL URODYNAM
Volume: 20
Issue: 2
First page : 197
Last page: 210
Number of pages: 14
ISSN: 0733-2467
DOI: https://doi.org/10.1002/1520-6777(2001)20:2<197::AID-NAU22>3.0.CO;2-F
Abstract
Micturition requires high bladder pressure and simultaneous opening of the urethra. In adult male rat, a rhabdosphincter (RB) is known to be electrically active when the bladder pressure is high. This indicates a closure rather than an opening of the urethra, which is inconsistent with the requirements of optimal urodynamics. In order to solve this problem, we simultaneously recorded electromyogram (EMG) of the proximal RB, bladder pressure, and Row rate. Micturition was evoked by an increased volume of saline in the bladder. A computer-based recording device was used with minimal filtering. The EMG was recorded with a monopolar flexible suction electrode. The suction electrode records action potentials resembling those obtained with a microelectrode technique. During the early high-frequency intraluminal pressure oscillation period (IPHFO). the increase of pressure initially associated with a decrease of potential of the RB. When the first how peak appeared. the relationship of the bladder pressure and RB single EMG activities changed. The increasing pressure coincided with the positive potential wave (depolarisation). It was interrupted by a transient negative polarity period called transient repolarisation (TRP) coinciding with a Row rate peak. thus indicating an opening of the RB lumen. After the TRP, the depolarisation continued. Additional experiments employing different methods are needed for positive identification of the TRP mechanism. (C) 2001 Wiley-Liss. Inc.
Micturition requires high bladder pressure and simultaneous opening of the urethra. In adult male rat, a rhabdosphincter (RB) is known to be electrically active when the bladder pressure is high. This indicates a closure rather than an opening of the urethra, which is inconsistent with the requirements of optimal urodynamics. In order to solve this problem, we simultaneously recorded electromyogram (EMG) of the proximal RB, bladder pressure, and Row rate. Micturition was evoked by an increased volume of saline in the bladder. A computer-based recording device was used with minimal filtering. The EMG was recorded with a monopolar flexible suction electrode. The suction electrode records action potentials resembling those obtained with a microelectrode technique. During the early high-frequency intraluminal pressure oscillation period (IPHFO). the increase of pressure initially associated with a decrease of potential of the RB. When the first how peak appeared. the relationship of the bladder pressure and RB single EMG activities changed. The increasing pressure coincided with the positive potential wave (depolarisation). It was interrupted by a transient negative polarity period called transient repolarisation (TRP) coinciding with a Row rate peak. thus indicating an opening of the RB lumen. After the TRP, the depolarisation continued. Additional experiments employing different methods are needed for positive identification of the TRP mechanism. (C) 2001 Wiley-Liss. Inc.
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