A1 Refereed original research article in a scientific journal
Variation in the dopamine D2 receptor gene plays a key role in human pain and its modulation by transcranial magnetic stimulation
Authors: Satu K. Jääskeläinen , Pauliina Lindholm, Tanja Valmunen, Ullamari Pesonen, Tero Taiminen, Arja Virtanen, Salla Lamusuo, Heli Forssell, Nora Hagelberg, Jarmo Hietala, Antti Pertovaara
Publisher: ELSEVIER SCIENCE BV
Publication year: 2014
Journal: PAIN
Journal name in source: PAIN
Journal acronym: PAIN
Volume: 155
Issue: 10
First page : 2180
Last page: 2187
Number of pages: 8
ISSN: 0304-3959
eISSN: 0304-3959
DOI: https://doi.org/10.1016/j.pain.2014.08.029
We tested whether variation of the dopamine D2 receptor (DRD2) gene contributes to individual differences in thermal pain sensitivity and analgesic efficacy of repetitive transcranial magnetic stimulation (rTMS) in healthy subjects (n = 29) or susceptibility to neuropathic pain in patients with neurophysiologically confirmed diagnosis (n = 16). Thermal sensitivity of healthy subjects was assessed before and after navigated rTMS provided to the S1/M1 cortex. All subjects were genotyped for the DRD2 gene 957C>T and catechol-O-methyltransferase (COMT) protein Val158Met polymorphisms. In healthy subjects, 957C>T influenced both innocuous and noxious thermal detection thresholds that were lowest in 957TT homozygotes (P values from .0277 to .0462). rTMS to S1 cortex had analgesic effect only in 957TT homozygote genotype (P = .0086). In patients, prevalence of 957TT homozygote genotype was higher than in a healthy Finnish population (50% vs 27%; P = .0191). Patients with 957TT genotype reported more severe pain than patients with other genotypes (P = .0351). COMT Val158Met polymorphism was not independently associated with the studied variables. Genetic regulation of DRD2 function by 957C>T polymorphism thus seems to influence thermal and pain sensitivity, its modulation by rTMS, and susceptibility to neuropathic pain. This indicates a central role for the dopamine system and DRD2 in pain and analgesia. This may have clinical implications regarding individualized selection of patients for rTMS treatment and assessment of risks for neuropathic pain. (C) 2014 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.