Striatal mu-opioid receptor availability predicts cold pressor pain threshold in healthy human subjects

: Hagelberg N, Aalto S, Tuominen L, Pesonen U, Nagren K, Hietala J, Scheinin H, Pertovaara A, Martikainen IK

Publisher: ELSEVIER IRELAND LTD

: 2012

: Neuroscience Letters

: NEUROSCIENCE LETTERS

: NEUROSCI LETT

: 1

: 521

: 1

: 11

: 14

: 4

: 0304-3940

DOI: https://doi.org/10.1016/j.neulet.2012.05.042

Previous PET studies in healthy humans have shown that brain mu-opioid receptor activation during experimental pain is associated with reductions in the sensory and affective ratings of the individual pain experience. The aim of this study was to find out whether brain mu-opioid receptor binding at the resting state, in absence of painful stimulation, can be a long-term predictor of experimental pain sensitivity. We measured mu-opioid receptor binding potential (BPND) with mu-opioid receptor selective radiotracer [C-11]carfentanil and positron emission tomography (PET) in 12 healthy male subjects. Later, we recruited these subjects to participate in a separate psychophysical testing session to measure cold pressor pain threshold, cold pressor pain tolerance and tactile sensitivity with von Frey monofilaments. We used both voxel-by-voxel and region-of-interest image analyses to examine the potential associations between mu-opioid receptor BPND and psychophysical measures. The results show that striatal mu-opioid receptor BPND predicts cold pressor pain threshold, but not cold pressor pain tolerance or tactile sensitivity. This finding suggests that striatal mu-opioid receptor density is involved in setting individual pain threshold. (C) 2012 Elsevier Ireland Ltd. All rights reserved.