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The Role of Intra-abdominal Pressure Measurement in Awake Rat Cystometry.

Lee T, Yoon SM - Int Neurourol J (2013)

Bottom Line: In awake cystometry, however, it is mandatory to separate the changes in intra-abdominal pressure from those in intravesical pressure, because consciousness causes much variability in intra-abdominal pressure.This review describes why we use the term "detrusor overactivity" in animal research with intra-abdominal pressure and presents evidence for the role of intra-abdominal pressure in the cystometry of normal rats and in animal models of overactive bladder directed at understanding the pathogenesis of the overactive bladder condition.The methodology is also briefly reviewed.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Inha University College of Medicine, Incheon, Korea.

ABSTRACT
Rat cystometry is increasingly being used in research on overactive bladder and is a research tool for investigating bladder functions during the storage and voiding phases. Measurement of the pressure in the bladder is an essential part of cystometry, although that pressure is the sum of both detrusor and intra-abdominal pressures. In anesthetic cystometry, measurement of the intra-abdominal pressure is not necessary, because the values of this variable are negligible. In awake cystometry, however, it is mandatory to separate the changes in intra-abdominal pressure from those in intravesical pressure, because consciousness causes much variability in intra-abdominal pressure. This review describes why we use the term "detrusor overactivity" in animal research with intra-abdominal pressure and presents evidence for the role of intra-abdominal pressure in the cystometry of normal rats and in animal models of overactive bladder directed at understanding the pathogenesis of the overactive bladder condition. The methodology is also briefly reviewed.

No MeSH data available.


Related in: MedlinePlus

Representative tracing showing the relations between intravesical, intra-abdominal, and detrusor pressure and flow of urine. IAP, intra-abdominal pressure; DP, detrusor pressure; IVP, intravesical pressure; F, flow; MP, micturition pressure. Adapted from Lee T, et al. Neurourol Urodyn 2008;27:88-95 [4].
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Figure 2: Representative tracing showing the relations between intravesical, intra-abdominal, and detrusor pressure and flow of urine. IAP, intra-abdominal pressure; DP, detrusor pressure; IVP, intravesical pressure; F, flow; MP, micturition pressure. Adapted from Lee T, et al. Neurourol Urodyn 2008;27:88-95 [4].

Mentions: Normal voiding is initiated and maintained by urethral relaxation followed by detrusor contraction, and abdominal straining is not always necessary. However, some humans, especially women, can initiate and maintain their micturition only by urethral relaxation and abdominal straining without detrusor contraction [10,11]. This suggests that the straining at voiding may have some other role in voiding that is not always pathologic. This can be initiated either voluntarily and consciously or instinctively and unconsciously and can result in pathologic or physiologic conditions. Patients with detrusor areflexia sometimes use pathologic straining, which leads to structural bladder wall changes such as trabeculations and diverticula [12]. However, recent animal studies have shown proof of physiologic straining in normal voiding. Cruz and Downie [11] investigated in healthy female rats whether the abdominal muscle contracts during voiding. They showed with electromyograms that the abdominal muscle is reflexively and consistently activated during physiological urine expulsion. In 2008, our group proved using the IAP methodology that all conscious rats of both sexes use this physiologic abdominal straining (Fig. 2) [4]. From a physics viewpoint, the contracting power of the bladder alone is not enough to allow the urine go out efficiently into the urethra. Some additional driving force is needed to deliver this power in one direction such as into the urethra. This abdominal straining seems to be a physiologic action in voiding that is induced instinctively and unconsciously.


The Role of Intra-abdominal Pressure Measurement in Awake Rat Cystometry.

Lee T, Yoon SM - Int Neurourol J (2013)

Representative tracing showing the relations between intravesical, intra-abdominal, and detrusor pressure and flow of urine. IAP, intra-abdominal pressure; DP, detrusor pressure; IVP, intravesical pressure; F, flow; MP, micturition pressure. Adapted from Lee T, et al. Neurourol Urodyn 2008;27:88-95 [4].
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3713241&req=5

Figure 2: Representative tracing showing the relations between intravesical, intra-abdominal, and detrusor pressure and flow of urine. IAP, intra-abdominal pressure; DP, detrusor pressure; IVP, intravesical pressure; F, flow; MP, micturition pressure. Adapted from Lee T, et al. Neurourol Urodyn 2008;27:88-95 [4].
Mentions: Normal voiding is initiated and maintained by urethral relaxation followed by detrusor contraction, and abdominal straining is not always necessary. However, some humans, especially women, can initiate and maintain their micturition only by urethral relaxation and abdominal straining without detrusor contraction [10,11]. This suggests that the straining at voiding may have some other role in voiding that is not always pathologic. This can be initiated either voluntarily and consciously or instinctively and unconsciously and can result in pathologic or physiologic conditions. Patients with detrusor areflexia sometimes use pathologic straining, which leads to structural bladder wall changes such as trabeculations and diverticula [12]. However, recent animal studies have shown proof of physiologic straining in normal voiding. Cruz and Downie [11] investigated in healthy female rats whether the abdominal muscle contracts during voiding. They showed with electromyograms that the abdominal muscle is reflexively and consistently activated during physiological urine expulsion. In 2008, our group proved using the IAP methodology that all conscious rats of both sexes use this physiologic abdominal straining (Fig. 2) [4]. From a physics viewpoint, the contracting power of the bladder alone is not enough to allow the urine go out efficiently into the urethra. Some additional driving force is needed to deliver this power in one direction such as into the urethra. This abdominal straining seems to be a physiologic action in voiding that is induced instinctively and unconsciously.

Bottom Line: In awake cystometry, however, it is mandatory to separate the changes in intra-abdominal pressure from those in intravesical pressure, because consciousness causes much variability in intra-abdominal pressure.This review describes why we use the term "detrusor overactivity" in animal research with intra-abdominal pressure and presents evidence for the role of intra-abdominal pressure in the cystometry of normal rats and in animal models of overactive bladder directed at understanding the pathogenesis of the overactive bladder condition.The methodology is also briefly reviewed.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Inha University College of Medicine, Incheon, Korea.

ABSTRACT
Rat cystometry is increasingly being used in research on overactive bladder and is a research tool for investigating bladder functions during the storage and voiding phases. Measurement of the pressure in the bladder is an essential part of cystometry, although that pressure is the sum of both detrusor and intra-abdominal pressures. In anesthetic cystometry, measurement of the intra-abdominal pressure is not necessary, because the values of this variable are negligible. In awake cystometry, however, it is mandatory to separate the changes in intra-abdominal pressure from those in intravesical pressure, because consciousness causes much variability in intra-abdominal pressure. This review describes why we use the term "detrusor overactivity" in animal research with intra-abdominal pressure and presents evidence for the role of intra-abdominal pressure in the cystometry of normal rats and in animal models of overactive bladder directed at understanding the pathogenesis of the overactive bladder condition. The methodology is also briefly reviewed.

No MeSH data available.


Related in: MedlinePlus