Rodent models of colorectal distension.

Colorectal distension (CRD) is a widely accepted, reproducible method for assessing visceral sensitivity in both clinical and pre-clinical studies. Distension of the colon mirrors the human scenario of visceral pain with regard to intensity and referral of pain in patients. There are several readouts that can be applied to the CRD protocol depending on the species being evaluated, two of which are described in this unit. CRD can be used to measure the impact of novel compounds, strain, or genetic differences as well as the effect of physical and psychological stressors on the sensitivity of the colon. Investigation of the impact of a noxious visceral stimulus (CRD) on other systems within the body can also be carried out. Given that visceral pain is a major clinical problem and one of the most common reasons patients seek out medical advice, the ability to assess this type of pain is essential to the discovery of successful treatments. This unit outlines two protocols that describe CRD of rats and mice.