Visceral pressure stimulator for exploring hollow organ pain: a pilot study

Abstract

Background The regulation and control of pressure stimuli is useful for many studies of pain and nociception especially those in the visceral pain field. In many in vivo experiments, distinct air and liquid stimuli at varying pressures are delivered to hollow organs such as the bladder, vagina, and colon. These stimuli are coupled with behavioral, molecular, or physiological read-outs of the response to the stimulus. Care must be taken to deliver precise timed stimuli during experimentation. For example, stimuli signals can be used online to precisely time-lock the stimulus with a physiological output. Such precision requires the development of specialized hardware to control the stimulus (e.g., air) while providing a precise read-out of pressure and stimulus signal markers. Methods In this study, we designed a timed pressure regulator [termed visceral pressure stimulator (VPS)] to control air flow, measure pressure (in mmHg), and send stimuli markers to online software. The device was built using a simple circuit and primarily off-the-shelf parts. A separate custom inline analog-to-digital pressure converter was used to validate the real pressure output of the VPS. Results Using commercial physiological software (Spike2, CED), we were able to measure mouse bladder pressure continuously during delivery of unique air stimulus trials in a mouse while simultaneously recording an electromyogram (EMG) of the overlying abdominal muscles. Conclusions This device will be useful for those who need to (1) deliver distinct pressure stimuli while (2) measuring the pressure in real-time and (3) monitoring stimulus on–off using physiological software.

Open source timed pressure control hardware and software for delivery of air mediated distensions in animal models

“…The second was a recently published visceral pain stimulator [10] . This device takes advantage of new microprocessors and microcontrollers to increase the flexibility and accessibility of previously published devices.…”

“…Similar data can be collected with our system, but it requires an external pressure sensor and amplifier. As a result, our device has the advantage of a more simplified design resulting in a slightly cheaper raw material cost (∼$200 here compared to ∼$500; estimated from the published parts list [10] ). Further, our system can be controlled directly with experimental software/hardware that many labs already use (Spike 2, LabView, etc.…”

Biomechanics of Hollow Organs: Experimental Testing and Computational Modeling

“…Mechanical tests at the structure level characterize the comprehensive mechanical behavior of the specific biological structure, accounting for the specific physiological function [27,28]. Further experimental activities aim to analyze organ behavior when novel clinical and/or surgical procedures are performed [29,30].…”