title: Melatonin and neurotrophins NT-3, BDNF, NGF in patients with varying levels of depression severity.
abstract: BACKGROUND
  Disrupted circadian rhythm of melatonin secretion in depression shows a relationship with the exacerbation of inflammatory processes. Proinflammatory mechanisms of depression are sustained by oxidative stress. This contributes to melatonin deficiency and to the malfunction of the defense mechanisms in the brain. Disrupted melatonin secretion in depression may have an influence on the concentrations of neurotrophic factors (NF), such as neurotrophin-3 (NT-3), brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). Disturbance in neurotrophin release may affect synaptic plasticity and cause exacerbation of neurodegenerative processes in the central nervous system. The aim of this study was to assess the concentrations of melatonin and NF of the brain in patients with varying levels of depression severity.
  
  
  METHODS
  160 males and females were enrolled in the study, 120 of whom were diagnosed with various types of depression. The control group comprised 40 healthy individuals. At 3:00a.m. all patients had salivary melatonin concentrations determined utilizing a competitive enzyme immunoassay technique (ELISA). In addition, at 7:00a.m. all patients had serum neurotrophin (NT-3, BDNF, NGF) concentrations determined by means of ELISA.
  
  
  RESULTS
  The highest melatonin secretion was observed at 3:00a.m. in severely depressed females. In the groups with mild and moderate depression, melatonin secretion at 3:00a.m. was comparable between males and females. In addition, a decrease in the concentrations of neurotrophins was revealed in patients at all levels of depression severity.
  
  
  CONCLUSIONS
  Melatonin may be a significant marker of depression severity. Melatonin and NF in depressed patients show neuroprotective effects.
authors.affiliation: Department of Psychiatry, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Toruń, Poland. Electronic address: e.oglodek@wp.pl.
authors.forename: Ewa A
authors.initials: EA
authors.lastname: Ogłodek
authors.affiliation: Department of General and Endocrine Surgery, Municipal Hospital in Piekary Śląskie, Piekary Śląskie, Poland.
authors.forename: Marek J
authors.initials: MJ
authors.lastname: Just
authors.affiliation: Silesian University of Technology in Gliwice, Gliwice, Poland.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Szromek
authors.affiliation: Department of Psychiatry, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, Toruń, Poland.
authors.forename: Aleksander
authors.initials: A
authors.lastname: Araszkiewicz
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism*; D003863:Depression / Q000378:metabolism*; D003866:Depressive Disorder / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008550:Melatonin / Q000378:metabolism*; D008875:Middle Aged; D020932:Nerve Growth Factor / Q000378:metabolism*; D009414:Nerve Growth Factors / Q000378:metabolism*; D009473:Neuronal Plasticity / Q000502:physiology; D020933:Neurotrophin 3; D055815:Young Adult
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C502240:NGF protein, human; C000595808:NTF3 protein, human; D009414:Nerve Growth Factors; D020933:Neurotrophin 3; C579455:BDNF protein, human; D020932:Nerve Growth Factor; D008550:Melatonin
keywords: Depression; Melatonin; Neurotrophins