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.