Best practices for cystometric evaluation of lower urinary tract function in muriform rodents

Abstract

Aims Rodent cystometry has provided valuable insights into the impact of the disease, injury, and aging on the cellular and molecular pathways, neurologic processes, and biomechanics of lower urinary tract function. The purpose of this white paper is to highlight the benefits and shortcomings of different experimental methods and strategies and to provide guidance on the proper interpretation of results. Methods Literature search, selection of articles, and conclusions based on discussions among a panel of workers in the field. Results A range of cystometric tests and techniques used to explore biological phenomena relevant to the lower urinary tract are described, the advantages and disadvantages of various experimental conditions are discussed, and guidance on the practical aspects of experimental execution and proper interpretation of results are provided. Conclusions Cystometric evaluation of rodents comprises an extensive collection of functional tests that can be performed under a variety of experimental conditions. Decisions regarding which approaches to choose should be determined by the specific questions to be addressed and implementation of the test should follow standardized procedures.

Choice of cystometric technique impacts detrusor contractile dynamics in wistar rats

“…Thus, these conduit‐associated phenomena likely contributed to a Pves curve with a continuous ascending phase without HFPO during the expulsion of urine or the rebound component that follows it. Use of a dual catheter system is therefore recommended when possible to avoid the pressure artifacts generated by pumping saline though the same tubing in order to record the low amplitude HFPOs and the plateau (Fraser et al, 2020). For single catheter use, strategies that can be used to enable observation of the HFPO include using a short and rigid catheter (Kontani, Kawabata, 1987, 2009; Kontani, Kobayashi, 1987) or reducing infusion rate (Watanabe & Constantinou, 1996; Watanabe et al, 1997).…”

“…During the third and final phase of micturition which begins with the closure of the EUS, an increase followed by a decrease in Pves was detected. Premature closing of the bladder outlet during an active detrusor contraction generates a rise of Pves due to new isovolumetric conditions (Fraser et al, 2020; Groen et al, 1994; Watanabe & Constantinou, 1996). In humans, the premature closure of the bladder outlet has been described as a cause of the after‐contraction phenomenon (Brantley et al, 1964; Zinner et al, 1963), which is considered a normal finding in healthy children.…”

“…Three phases of the CMG include an initial rise in intra‐vesical pressure (Pves) generated by the detrusor's contraction under isovolumetric conditions, an emptying phase identified by phasic contractions of the external urethral sphincter (EUS) which provokes sudden and rhythmic Pves increases known as high frequency pressure oscillations (HFPO) with concurrent loss of pressure during the expulsion of urine (which generates a plateau shape in the Pves record), and a third phase characterized by a Pves increase known as rebound (Andersson et al, 2011; Maggi et al, 1986; Wu et al, 2018). The incidence and contributing factors to the rebound phase have yet to be elucidated, although it has been proposed to be a closing pressure spike (Fraser et al, 2020). In addition, CMG recordings are known to be disrupted by the type of anesthesia used including its route of administration (Cannon & Damaser, 2001; Chang & Havton, 2008; He et al, 2020) as well as the physical properties of the set‐up (tubing size, pump speed), which can induce systematic and random observational errors (Hogan et al, 2012; Lotze, 2005).…”

Blockade of Acid-Sensing Ion Channels Increases Urinary Bladder Capacity With or Without Intravesical Irritation in Mice

“…All cystometric evaluations were conducted under unanesthetized conditions in decerebrated mice to assess 'reflex micturition'. Pros and cons when using this animal model have been described elsewhere (Fraser et al, 2020). Saline (pH 6.3) was infused into the bladder for 2 h before baseline values were measured.…”

“…Bladder activity was monitored by way of a cystometry catheter connected to a pressure transducer. Cystometric recordings were performed by continuously infusing physiological saline (30 µl/min) at room temperature into the bladder to elicit repetitive voids, which allowed data collection for a large number of voiding cycles (Maggi et al, 1986;Fraser et al, 2020). As shown in Figure 1, cystometric parameters measured were: pressure threshold (PT; mmHg), the intraluminal pressure required to induce a voiding contraction; maximal voiding pressure (MVP; mmHg), the peak intraluminal pressure during voiding; closing peak pressure (CPP; mmHg), the peak pressure during the postvoiding phase of a bladder contraction; resting pressure (RP; mmHg), the lowest pressure immediately after a voiding contraction; and intercontraction interval (ICI; s), the time lag between two voiding cycles.…”