title: Thalamic glutamate decreases with cigarette smoking.
abstract: BACKGROUND
  Findings from animal studies and human PET imaging indicate that nicotine and cigarette smoking affect glutamate (Glu) and related neurochemical markers in the brain and imply that smoking reduces extracellular Glu. As Glu release is mediated by nicotinic acetylcholine receptors (nAChRs), which are present at high concentrations in the thalamus, we examined the effects of smoking on thalamic Glu.
  
  
  OBJECTIVE
  To determine the effects of tobacco smoking on thalamic glutamate levels.
  
  
  METHODS
  Thalamic Glu levels were measured in vivo in 18 smokers and 16 nonsmokers using proton magnetic resonance spectroscopic imaging ((1)H MRSI) at 1.5 T.
  
  
  RESULTS
  Mean Glu levels did not differ significantly between the subject groups. However, within smokers, Glu levels were negatively correlated with self-reports of both cigarettes/day over the last 30 days (r = -0.64, p = 0.006) and pack-years of smoking (r = -0.66, p = 0.005).
  
  
  CONCLUSIONS
  Consistent with expectations based on preclinical studies, within smokers, cigarettes/day and pack-years are associated with reduced Glu in thalamus, a brain region rich in nAchRs. These results encourage work on candidate glutamatergic therapies for smoking cessation and suggest a noninvasive metric for their action in the brain.
authors.affiliation: Division of Child & Adolescent Psychiatry, UCLA Semel Institute for Neuroscience, 760 Westwood Plaza, Box 175919, Los Angeles, CA, 90024-1759, USA, joneill@mednet.ucla.edu.
authors.forename: Joseph
authors.initials: J
authors.lastname: O'Neill
authors.forename: Marc C
authors.initials: MC
authors.lastname: Tobias
authors.forename: Matthew
authors.initials: M
authors.lastname: Hudkins
authors.forename: Eugene Y
authors.initials: EY
authors.lastname: Oh
authors.forename: Gerhard S
authors.initials: GS
authors.lastname: Hellemann
authors.forename: Erika L
authors.initials: EL
authors.lastname: Nurmi
authors.forename: Edythe D
authors.initials: ED
authors.lastname: London
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D006801:Humans; D008297:Male; D066244:Proton Magnetic Resonance Spectroscopy / Q000379:methods; D011978:Receptors, Nicotinic / Q000378:metabolism*; D012907:Smoking / Q000378:metabolism*; D013788:Thalamus / Q000378:metabolism*; D013997:Time Factors
chemical_list: D011978:Receptors, Nicotinic; D018698:Glutamic Acid