Pain Model Validation
Research type
Research Study
Full title
Validation of a human experimental pain model for the evaluation of centrally mediated noradrenergic and opiod analgesic mechanisms
IRAS ID
119002
Contact name
Richard Langford
Contact email
Sponsor organisation
Research and Development, Barts Health NHS Trust
Research summary
Chronic pain is complex and challenging condition in medicine, with a huge impact on individuals, family and the economy. So far we have limited treatment options that pose co-existent tolerability and safety issues. We wish to validate a pain model that will give us a better understanding of pain pathways. This is not a completely novel technique or idea. The R3 reflex is an innate response of reflex withdrawal from pain, it involves a nerve circuit that involves pain nerves to the spinal cord and then nerves to muscles. The nerves we will stimulate are at the ankle and the muscle response will be recorded in the thigh. This technique has been studied for over thirty years. It is a useful phenomenon in understanding pain because it is objective, reproducible and very robust, and so is less prone to bias. It is a temporary effect that is not harmful and acceptable to patients.
We wish to validate this pain model using two different pain pathways to see the effect of their modulation. The opioid system is known to provide pain relief by acting in the brain, spinal cord as well as the peripheral nerves. The neurohormone noradrenaline is also known to act on the spinal cord to inhibit the pain signal.
We will study the R3 reflex in twenty patients using a cross-over design that will assign subjects randomly, in order to improve the power of the findings and minimise bias by blinding both subjects and investigators to which group the subject is in.
REC name
London - City & East Research Ethics Committee
REC reference
13/LO/0861
Date of REC Opinion
18 Sep 2013
REC opinion
Further Information Favourable Opinion