Sunshine-exposure variation of human striatal dopamine D(2)/D(3) receptor availability in healthy volunteers

Prog Neuropsychopharmacol Biol Psychiatry. 2011 Jan 15;35(1):107-10. doi: 10.1016/j.pnpbp.2010.09.014. Epub 2010 Sep 26.


Background: In addition to the serotonergic system, the central dopaminergic system has been reported to be correlated with seasonality. The aim of this study was to explore the difference in striatal dopamine D(2)/D(3) receptor availability between healthy volunteers who had a high-sunshine exposure and those who had a low exposure.

Methods: Sixty-eight participants were enrolled, and those in the upper and lower quartiles in terms of sunshine exposure were categorized into high- (n = 17) and low-sunshine-exposure (n = 18) subgroups. Single photon emission computed tomography with [(123)I] iodo-benzamide was used to measure striatal dopamine D(2)/D(3) receptor availability.

Results: Striatal dopamine D(2)/D(3) receptor availability was significantly greater in the subjects with high-sunshine exposure than in those with low-sunshine exposure (F = 7.97, p = 0.01) after controlling for age, sex, and smoking status.

Limitations: Different subjects were examined at different time points in our study. In addition, the sex and tobacco use distributions differed between groups.

Conclusion: The central dopaminergic system may play a role in the neurobiological characteristics of sunshine-exposure variation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Benzamides / pharmacokinetics
  • Corpus Striatum / diagnostic imaging
  • Corpus Striatum / drug effects
  • Corpus Striatum / metabolism*
  • Dopamine Antagonists / pharmacokinetics
  • Female
  • Humans
  • Male
  • Middle Aged
  • Protein Binding / drug effects
  • Pyrrolidines / pharmacokinetics
  • Receptors, Dopamine D2 / metabolism*
  • Receptors, Dopamine D3 / metabolism*
  • Retrospective Studies
  • Seasons
  • Sunlight*
  • Tomography, Emission-Computed, Single-Photon / methods
  • Young Adult


  • Benzamides
  • Dopamine Antagonists
  • Pyrrolidines
  • Receptors, Dopamine D2
  • Receptors, Dopamine D3
  • 3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide