TITLE:
Influence of Intravesical Lower pH on the Micturition Reflex Threshold in the Rat
AUTHORS:
Peng Zeng, Shaohua Zeng, Chonghe Jiang, Janwen Zeng, Jianfeng Mo, Sivert Lindström
KEYWORDS:
pH, Urinary Bladder, Micturition Threshold Volume, Afferent, Efferent, Rat
JOURNAL NAME:
Open Journal of Urology,
Vol.4 No.12,
December
5,
2014
ABSTRACT: Aims: To investigate whether intravesical
lower pH induces a micturition threshold reflex change of anaesthetized rats.
Methods: Thirteen female rats, anaesthetized by a-chloralose
and paralyzed by pancurone bromide were used for the experiments. The micturition
threshold volume was determined by repeated cystometry. Simultaneously bladder
afferent activities in four and efferent activities in seven rats were recorded
from the exposed pelvic nerve to the bladder. Results: Cystometry with acidic
saline at pH 3 and 4 induced a significant decrease in micturition threshold
volume. The mean value of these groups of test showed that bladder compliance,
micturition threshold pressure and maximal micturition contraction pressure
were decreased significantly comparing with the controls. There were no changes
in all other parameters recorded from afferent and efferent, e.g. afferent
threshold volume, afferent or efferent activity at the micturition threshold
and their peak activity at the micturition contraction. Conclusions: Acidic
solution provoked sensitivity but reduced the force of the contractility to the
urinary bladder. The effect was presented without a detectable change in the
firing properties of bladder Ad mechanoreceptor afferents. It is proposed that proton sensitive
bladder receptors with unmyelinated afferent were stimulated by the acidic
solution and that the micturition reflex was facilitated by afferent inflow
from such receptors. The findings were clinically important in choosing the
medium for urodynamic examination.