title: The impact of serotonin on the development of bystander damage assessed by γ-H2AX foci analysis.
abstract: OBJECTIVE
  This investigation addresses the question of whether serum constituents have a modulating effect on the induction of bystander effects. It was carried out as part of an inter-laboratory comparison-exercise within the European Union-integrated project NOTE (Non-targeted effects of ionizing radiation). Serotonin is a neurotransmitter, which is present in the circulatory system and therefore in blood serum. Fetal bovine serum is an essential supplement to most cell culture media and contains different, batch-dependent concentrations of serotonin. In a recent publication, serotonin was found to have a strong modulating effect on the size of bystander effects detected using colony formation assays.
  
  
  METHODS
  We tested modulatory effects on bystander response detected by γ-H2AX (phosphorylated histone H2AX) foci formation in cells exposed to media of irradiated cells. Cells were grown in serum batches with different serotonin concentrations.
  
  
  RESULTS
  While the data obtained with the three serum batches examined show a trend for increasing bystander response with increasing serotonin concentration, the effect failed to reach statistical significance.
  
  
  CONCLUSIONS
  Serotonin may have a modulating effect on radiation-induced bystander effects, but more work is required to conclusively characterize this contribution.
authors: Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, Essen, Germany. Georg.Iliakis@uk-essen.de
authors: Holger
authors: H
authors: Klammer
authors: George
authors: G
authors: Iliakis
mesh_terms: D000818:Animals; D024201:Bystander Effect / Q000187:drug effects* / Q000235:genetics / Q000528:radiation effects*; D002417:Cattle; D045744:Cell Line, Tumor; D003470:Culture Media / Q000737:chemistry; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D006657:Histones / Q000378:metabolism*; D006801:Humans; D012701:Serotonin / Q000494:pharmacology*
chemical_list: D003470:Culture Media; C468783:H2AX protein, human; D006657:Histones; D012701:Serotonin