title: Serotonergic effects of smoking are independent from the human serotonin transporter gene promoter polymorphism: evidence from auditory cortical stimulus processing.
abstract: BACKGROUND
  Cigarette smoking has been associated with mood enhancing properties and modulating effects on serotonin activity. The loudness dependence (LD) of the auditory-evoked N1/P2-component has been related to serotonergic neurotransmission, i. e. the allelic variants in the promoter of the 5-hydroxytryptamine-transporter (5-HTT) gene (SCL6A4). Moreover, smoking behavior has been associated to the 5-HTT-genotype. It was hypothesized that cigarette smoking modulates the LD and this effect was expected to interact with the 5-HTT-genotype.
  
  
  METHODS
  5-HTT-genotype and LD were determined in 63 healthy smokers and 114 nonsmokers.
  
  
  RESULTS
  LD was significantly affected by smoking status (p = 0.008) and 5-HTT-genotype (p = 0.045) but not by smoking*genotype-interaction or daily cigarette consumption. Current smokers exhibited a significantly weaker LD compared to nonsmokers. 5-HTT-genotype showed no significant effect on smoking behavior.
  
  
  CONCLUSIONS
  The results indicate a higher serotonergic activity in smokers as compared to nonsmokers independent of 5-HTT-genotype. Since former smokers and never smokers showed similar LDs, the serotonin enhancing effect of smoking seems to be a characteristic state, which may contribute to the maintenance of smoking behavior.
authors: Clinic for Psychiatry and Psychotherapy, Charité University Medicine, Campus Mitte, Berlin, Germany. juergen.gallinat@charite.de
authors: J
authors: J
authors: Gallinat
authors: D
authors: D
authors: Kunz
authors: U E
authors: UE
authors: Lang
authors: P
authors: P
authors: Kalus
authors: G
authors: G
authors: Juckel
authors: J
authors: J
authors: Eggers
authors: R
authors: R
authors: Mahlberg
authors: M
authors: M
authors: Staedtgen
authors: C
authors: C
authors: Wernicke
authors: H
authors: H
authors: Rommelspacher
authors: M N
authors: MN
authors: Smolka
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D004247:DNA / Q000235:genetics; D005072:Evoked Potentials, Auditory / Q000502:physiology; D005260:Female; D005838:Genotype; D006801:Humans; D008144:Loudness Perception / Q000502:physiology; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism*; D011110:Polymorphism, Genetic / Q000235:genetics; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012701:Serotonin / Q000502:physiology*; D050486:Serotonin Plasma Membrane Transport Proteins; D012907:Smoking / Q000378:metabolism*
chemical_list: D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D012701:Serotonin; D004247:DNA