Dopamine efflux in response to ultraviolet radiation in addicted sunbed users

Psychiatry Res Neuroimaging. 2016 May 30;251:7-14. doi: 10.1016/j.pscychresns.2016.04.001. Epub 2016 Apr 7.

Abstract

Compulsive tanning despite awareness of ultraviolet radiation (UVR) carcinogenicity may represent an "addictive" behavior. Many addictive disorders are associated with alterations in dopamine (D2/D3) receptor binding and dopamine reactivity in the brain's reward pathway. To determine if compulsive tanners exhibited neurobiologic responses similar to other addictive disorders, this study assessed basal striatal D2/D3 binding and UVR-induced striatal dopamine efflux in ten addicted and ten infrequent tanners. In a double-blind crossover trial, UVR or sham UVR was administered in separate sessions during brain imaging with single photon emission computerized tomography (SPECT). Basal D2/D3 receptor density and UVR-induced dopamine efflux in the caudate were assessed using (123)I-iodobenzamide ((123)I-IBZM) binding potential non-displaceable (BPnd). Basal BPnd did not significantly differ between addicted and infrequent tanners. Whereas neither UVR nor sham UVR induced significant changes in bilateral caudate BPnd in either group, post-hoc analyses revealed left caudate BPnd significantly decreased (reflecting increased dopamine efflux) in the addicted tanners - but not the infrequent tanners - during the UVR session only. Bilateral ∆BPnd correlated with tanning severity only in the addicted tanners. These preliminary findings are consistent with a stronger neural rewarding response to UVR in addicted tanners, supporting a cutaneous-neural connection driving excessive sunbed use.

Keywords: Addiction; Dopamine; Imaging; Mesostriatal reward system; SPECT; Tanning.

MeSH terms

  • Adult
  • Behavior, Addictive / diagnosis
  • Behavior, Addictive / metabolism*
  • Behavior, Addictive / psychology*
  • Brain / metabolism*
  • Corpus Striatum / metabolism
  • Dopamine / metabolism*
  • Double-Blind Method
  • Female
  • Humans
  • Neostriatum / metabolism
  • Radiopharmaceuticals / metabolism
  • Receptors, Dopamine D2 / metabolism
  • Reward
  • Sunbathing / psychology*
  • Tomography, Emission-Computed, Single-Photon / methods
  • Ultraviolet Rays* / adverse effects

Substances

  • Radiopharmaceuticals
  • Receptors, Dopamine D2
  • Dopamine