Int Neurourol J.  2018 Mar;22(1):9-19. 10.5213/inj.1835052.526.

Synergistic Activities of Abdominal Muscles Are Required for Efficient Micturition in Anesthetized Female Mice

• Zhang C
• Zhang Y
• Cruz Y
• Boone TB
• Munoz A

• KMID: 2409723
• DOI: http://doi.org/10.5213/inj.1835052.526

Abstract

PURPOSE
To characterize the electromyographic activity of abdominal striated muscles during micturition in urethane-anesthetized female mice, and to quantitatively evaluate the contribution of abdominal responses to efficient voiding.
METHODS
Cystometric and multichannel electromyographic recordings were integrated to enable a comprehensive evaluation during micturition in urethane-anesthetized female mice. Four major abdominal muscle domains were evaluated: the external oblique, internal oblique, and superior and inferior rectus abdominis. To further characterize the functionality of the abdominal muscles, pancuronium bromide (25 μg/mL or 50 μg/mL, abdominal surface) was applied as a blocking agent of neuromuscular junctions.
RESULTS
We observed a robust activation of the abdominal muscles during voiding, with a consistent onset/offset concomitant with the bladder pressure threshold. Pancuronium was effective, in a dose-dependent fashion, for partial and complete blockage of abdominal activity. Electromyographic discharges during voiding were significantly inhibited by applying pancuronium. Decreased cystometric parameters were recorded, including the peak pressure, pressure threshold, intercontractile interval, and voiding duration, suggesting that the voiding efficiency was significantly compromised by abdominal muscle relaxation.
CONCLUSIONS
The relevance of the abdominal striated musculature for micturition has remained a topic of debate in human physiology. Although the study was performed on anesthetized mice, these results support the existence of synergistic abdominal electromyographic activity facilitating voiding in anesthetized mice. Further, our study presents a rodent model that can be used for future investigations into micturition-related abdominal activity.

Keyword

Lower urinary tract symptoms; Micturition; Abdominal muscles; Electromyography; Cystometry

MeSH Terms

Abdominal Muscles*
Animals
Electromyography
Female*
Humans
Lower Urinary Tract Symptoms
Mice*
Muscle, Striated
Neuromuscular Junction
Pancuronium
Physiology
Rectus Abdominis
Relaxation
Rodentia
Urinary Bladder
Urination*
Pancuronium