title: Sunshine-exposure variation of human striatal dopamine D(2)/D(3) receptor availability in healthy volunteers.
abstract: 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.
  
  
  CONCLUSIONS
  Different subjects were examined at different time points in our study. In addition, the sex and tobacco use distributions differed between groups.
  
  
  CONCLUSIONS
  The central dopaminergic system may play a role in the neurobiological characteristics of sunshine-exposure variation.
authors.affiliation: Department of Psychiatry, St Martin De Porres Hospital, Chiayi, Taiwan.
authors.forename: Hsiang-Yi
authors.initials: HY
authors.lastname: Tsai
authors.forename: Kao Chin
authors.initials: KC
authors.lastname: Chen
authors.forename: Yen Kuang
authors.initials: YK
authors.lastname: Yang
authors.forename: Po See
authors.initials: PS
authors.lastname: Chen
authors.forename: Tzung Lieh
authors.initials: TL
authors.lastname: Yeh
authors.forename: Nan Tsing
authors.initials: NT
authors.lastname: Chiu
authors.forename: I Hui
authors.initials: IH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001549:Benzamides / Q000493:pharmacokinetics; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000187:drug effects / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011485:Protein Binding / Q000187:drug effects; D011759:Pyrrolidines / Q000493:pharmacokinetics; D017448:Receptors, Dopamine D2 / Q000378:metabolism*; D050637:Receptors, Dopamine D3 / Q000378:metabolism*; D012189:Retrospective Studies; D012621:Seasons; D013472:Sunlight; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D055815:Young Adult
chemical_list: D001549:Benzamides; D018492:Dopamine Antagonists; D011759:Pyrrolidines; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; C055743:3-iodo-2-hydroxy-6-methoxy-N-((1-ethyl-2-pyrrolidinyl)methyl)benzamide