October 2013 NUI Galway researchers publish new findings on the brain’s marijuana-like chemicals in stress-pain interactions

New findings investigating the influence of a stress-sensitive genetic background on pain have been published in the leading journal in the field Pain, by NUI Galway researchers. The work, funded by Science Foundation Ireland and the Irish Research Council, was carried out by Dr David Finn and his research team in Pharmacology and Therapeutics, Centre for Pain Research and Galway Neuroscience Centre at the National Centre for Biomedical Engineering Science, NUI Galway.

Heightened pain in individuals who are stressed, anxious or depressed is a widely recognized but poorly understood phenomenon. A key factor is the contribution of genetic background and its influence on stress responding and emotional processing. A particular genetic background can predispose individuals to higher stress, anxiety and pain responses but it is not known why. 

Previous findings have shown that pain is subject to influence by marijuana-like chemicals called endocannabinoids in a brain region called the rostral ventromedial medulla.  Working with Dr Finn, first author Dr Kieran Rea was able to show that a genetic background associated with higher stress and anxiety responses was associated with a greater pain response and a blunted response of these endocannabinoids in the part of the brain called the rostral ventromedial medulla.

Furthermore, this enhanced pain response was prevented by a drug that increased levels of these endocannabinoids in this part of the brain.  Further experimentation revealed that blockade of the cannabinoid CB1 receptor, at which these endocannabinoids act, exacerbated the pain response.

An increased understanding of how genetic background associated with stress and anxiety can influence pain is important from a fundamental physiological perspective and may also aid the identification of new ways of treating  persistent pain and the impact of  stress-related psychiatric disorders such anxiety or depression.

Dr David Finn, Leader of the Galway Neuroscience Centre, Co-Director of the Centre for Pain Research at NUI Galway and study leader says: “The link between emotionality and pain is fascinating and highly complex.  This research suggests a key role for the brain’s endocannabinoid system in a genetic background prone to heighted stress or negative emotion. This research, which was funded by a grant from Science Foundation Ireland, advances our understanding of the neurobiology of pain and may facilitate the identification of new therapeutic targets for the treatment of pain and psychiatric disorders.”

Rea K, Olango W, Okine B, Madasu M, McGuire IC, Coyle K, Harhen B, Roche M, Finn DP (2013) Pain; Online publication: 24 Sept 2013; DOI: 10.1016/j.pain.2013.09.012

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