title: Gender and age related changes in number of dopaminergic neurons in adult human olfactory bulb.
abstract: BACKGROUND
  Dopamine is one of the major brain neurotransmitters, and the loss of dopaminergic neurons in basal ganglia cause motor deficits in Parkinson's disease. We proposed that the difficulty in olfaction observed in the elderly may be due to an alteration in the number of dopaminergic neurons.
  
  
  METHODS
  Sections were taken from olfactory bulbs of post-mortem tissue specimens of 13 humans, males and females, aged from 19 to 63 years (≤35 and ≥50 years), with no history of neurological disorders. The tissues were fixed, embedded, cut on a freezing microtome, and prepared for immunohistochemical analysis using tyrosine hydroxylase (TH) and aromatic l-amino acid decarboxylase (AADC) antibodies. The number of positive neurons was counted.
  
  
  RESULTS
  TH- and AADC-positive cells were present in the glomerular layer. There was no significant difference between the numbers of TH- and AADC-positive cells, in males and females, and in young and elderly individuals. The quantitative analysis revealed that the number of TH- and AADC-positive neurons were significantly higher in males than in females (P<0.05). Moreover, there was a significant increase in the number of TH- and AADC-positive neurons in the olfactory bulbs of the elderly compared with young individuals (P<0.05).
  
  
  CONCLUSIONS
  Factors such as gender and age may affect the number of dopaminergic neurons, and there is a correlation between increased dopaminergic neurons and olfactory performance. Moreover, the increase in dopaminergic cells in the olfactory bulb of the elderly may indicate the existence of rostral migratory stream in adult humans.
authors.affiliation: Cellular and Molecular Research Center, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran; Department of Anatomy, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Rafieh
authors.initials: R
authors.lastname: Alizadeh
authors.affiliation: Department of Anatomy, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Gholamreza
authors.initials: G
authors.lastname: Hassanzadeh
authors.affiliation: Cellular and Molecular Research Center, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran; Department of Anatomy, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mansoureh
authors.initials: M
authors.lastname: Soleimani
authors.affiliation: Cellular and Molecular Research Center, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran; Department of Anatomy, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Mohammad Taghi
authors.initials: MT
authors.lastname: Joghataei
authors.affiliation: Department of Clinical Pathology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran.
authors.forename: Vahid
authors.initials: V
authors.lastname: Siavashi
authors.affiliation: Iranian Tissue Bank and Research Center, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Zhinoos
authors.initials: Z
authors.lastname: Khorgami
authors.affiliation: Brain and Spinal cord Injury Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Neuroscience, School of Advanced Medical Sciences, Tehran University of Medical Sciences, Tehran, Iran; Shefa Neuroscience Research Center, Tehran, Iran. Electronic address: mhadjighassem@tums.ac.ir.
authors.forename: Mahmoudreza
authors.initials: M
authors.lastname: Hadjighassem
mesh_terms: D000328:Adult; D000367:Age Factors; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000032:analysis / Q000378:metabolism; D002452:Cell Count; D004298:Dopamine / Q000378:metabolism / Q000502:physiology*; D059290:Dopaminergic Neurons / Q000737:chemistry / Q000166:cytology* / Q000201:enzymology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009830:Olfactory Bulb / Q000737:chemistry / Q000166:cytology* / Q000201:enzymology; D012737:Sex Factors; D012903:Smell; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis / Q000378:metabolism; D055815:Young Adult
chemical_list: D014446:Tyrosine 3-Monooxygenase; D001142:Aromatic-L-Amino-Acid Decarboxylases; D004298:Dopamine
keywords: Age; Aromatic l-amino acid decarboxylase; Dopaminergic neurons; Gender; Human olfactory bulb; Tyrosine hydroxylase