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Updated: Aug 11, 2026
Detrusor Underactivity Model in Rats by Conus Medullaris Transection
Published on: August 28, 2020
Impaired micturition reflex caused by acute selective dorsal or ventral root(s) rhizotomy in anesthetized rats
Jiuan-Miaw Liao1, Chen-Li Cheng2, Shin-Da Lee3
1Department of Physiology, College of Medicine, Chung-Shan Medical University, Taichung, Taiwan.
Purpose:
To clarify the contributions of parasympathetic inputs and outputs to the micturition reflex.
Materials And Methods:
Intra-vesical pressure (IVP), external urethral sphincter electromyogram (EMG), pelvic afferent nerve activities (PANA), and pelvic efferent nerve activities (PENA) as well as the time-derived IVP (dIVP, an index of bladder contractility) were evaluated in intact and acute dorsal or ventral root(s) rhizotomized (DRX and VRX, respectively) rats.
Results:
In DRX rats, when compared with that in intact stage, the voiding frequency was decreased (75 +/- 15% of intact, P < 0.05, n = 8), while the threshold pressure to trigger voiding contractions was significantly increased (187 +/- 75% of intact, P < 0.05, n = 8). In addition, several insufficient contractions (5.3 +/- 3.5 contractions/voiding, P < 0.05, n = 8) occurred in ahead of each voiding contraction. On the other hand, in VRX rats, the peak and rebound IVP were significantly decreased (90 +/- 3.5% and 75 +/- 11.3% of intact, P < 0.01, n = 8), while the threshold pressure was not affected (102 +/- 11% of intact, P = NS, n = 8). The time-derived parameters were significantly decreased in VRX (peak dIVP, 78 +/- 10.2%, rebound dIVP, 75 +/- 15.6%, minimal dIVP, 68 +/- 14% of intact, P < 0.01, n = 8) but only peak dIVP was decreased (85 +/- 11% of intact, P < 0.01, n = 8) in DRX rats.
Conclusion:
Acute selective DRX and VRX rat can be an animal model to investigate peripheral neural control in micturition functions.
