Pressure-volume analysis of rat's micturition cycles in vivo

Hsien Yu Peng, Cheng Yuan Lai, Ming Chun Hsieh, Yu Cheng Ho, Tzer Bin Lin

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Aims: Though the pressure-volume analysis (PVA), a method based on thermodynamics, is broadly used for assaying cardiac functions, its potential application on the physiology/pathophysiology of the urinary bladder, which processes resemble thermodynamic cycles to the heart, has not been established. Methods: Cystometry recording intravesical pressure (IVP) and intravesical volume (IVV) of rhythmic voiding contractions caused by a constant saline infusion (0.04 mL/min) were carried out in forty urethane-anesthetized female Sprague-Dawley rats, and the PVA was established by plotting IVP against IVV. Results: Pressure-volume points shaped coincident enclosed loops, and loop-associated urodynamic parameters kept stable under a constant infusion rate (0.04 mL/min). Enhancing preload (by elevating infusion rates to 0.08 and 0.12 mL/min) increased the area enclosed by the loop (Apv) and shifted loops to the right and slightly upward. Augmenting afterload (by enhancing resistances using 1/4 and 1/2 urethra clamping) increased Apv and shifted loops markedly to the right and upward. Without affecting Apv, muscarine (0.01 and 0.1 mM)-induced inotropic states shifted loop to the left and upward that was as opposed to the atropine (0.01 and 0.1 mM)-induced anti-inotropic state. Conclusions: Not only consistently assayed baseline bladder functions, PVA but also validly measured modified bladder functions due to altered extrinsic environment and intrinsic contractility of the bladder itself. In accompanied by cystometry, PVA could provide a clear concept about the relationship between time, pressure, and volume in the voiding activity.

Original languageEnglish
Pages (from-to)1304-1312
Number of pages9
JournalNeurourology and Urodynamics
Volume39
Issue number5
DOIs
Publication statusPublished - Jun 1 2020

Keywords

  • micturition
  • pressure-volume loop
  • rat
  • thermodynamics
  • urinary bladder

ASJC Scopus subject areas

  • Clinical Neurology
  • Urology

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