The genetic influence on the cortical processing of experimental pain and the moderating effect of pain status.
BACKGROUND
Research suggests that the COMT Val(158)Met, BDNF Val(66)Met and OPRM1 A(118)G polymorphisms moderate the experience of pain. In order to obtain experimental confirmation and extension of findings, cortical processing of experimentally-induced pain was used.


METHODS
A sample of 78 individuals with chronic low back pain complaints and 37 healthy controls underwent EEG registration. Event-Related Potentials were measured in response to electrical nociceptive stimuli and moderation by COMT Val(158)Met, BDNF Val(66)Met and OPRM1 A(118)G polymorphisms was assessed.


RESULTS
Genetic variation did not have a direct effect on cortical processing of experimental pain. However, genetic effects (COMT Val(158)Met and BDNF Val(66)Met) on experimental pain were moderated by the presence of chronic pain. In the presence of chronic pain, the COMT Met allele and the BDNF Met allele augmented cortical pain processing, whilst reducing pain processing in pain-free controls. No significant effects were found concerning the OPRM1 A(118)G polymorphism.


CONCLUSIONS
The current study suggests that chronic experience of pain enhances genetic sensitivity to experimentally induced mildly painful stimuli, possibly through a process of epigenetic modification.
Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, The Netherlands. helen.vossen@gmail.com
Helen
H
Vossen
Gunter
G
Kenis
Bart
B
Rutten
Jim
J
van Os
Hermie
H
Hermens
Richel
R
Lousberg
D000328:Adult; D019208:Brain-Derived Neurotrophic Factor / Q000737:chemistry / Q000235:genetics; D016022:Case-Control Studies; D002394:Catechol O-Methyltransferase / Q000737:chemistry / Q000235:genetics; D002540:Cerebral Cortex / Q000503:physiopathology*; D002908:Chronic Disease; D004569:Electroencephalography; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000235:genetics / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D017450:Receptors, Opioid, mu / Q000737:chemistry / Q000235:genetics
D019208:Brain-Derived Neurotrophic Factor; C485764:OPRM1 protein, human; D017450:Receptors, Opioid, mu; D002394:Catechol O-Methyltransferase