title: Influences of smoking and caffeine consumption on trigeminal pain processing.
abstract: BACKGROUND
  Many human and animal studies have shown the influence of nicotine and caffeine on pain perception and processing. This study aims to investigate whether smoking or caffeine consumption influences trigeminal pain processing.
  
  
  METHODS
  Sixty healthy subjects were investigated using simultaneous recordings of the nociceptive blink reflex (nBR) and pain related evoked potentials (PREP) following nociceptive electrical stimulation on both sides of the forehead (V1). Thirty subjects were investigated before and after smoking a cigarette, as well as before and after taking a tablet of 400 mg caffeine.
  
  
  RESULTS
  After smoking PREP showed decreased N2 and P2 latencies indicating central facilitation at supraspinal (thalamic or cortical) level. PREP amplitudes were not changed. NBR showed a decreased area under the curve (AUC) indicating central inhibition at brainstem level. After caffeine intake no significant changes were observed comparing nBR and PREP results before consumption.
  
  
  CONCLUSIONS
  Smoking influences trigeminal pain processing on supraspinal and brainstem level. In the investigated setting, caffeine consumption does not significantly alter trigeminal pain processing. This observation might help in the further understanding of the pathophysiology of pain disorders that are associated with excessive smoking habits such as cluster headache. Previous smoking has to be taken into account when performing electrophysiological studies to avoid bias of study results.
authors.affiliation: Department of Neurology, University of Duisburg-Essen, Hufeland street 55, Essen 45147, Germany. dagny.holle@uk-essen.de.
authors.forename: Dagny
authors.initials: D
authors.lastname: Holle
authors.forename: Anke
authors.initials: A
authors.lastname: Heber
authors.forename: Steffen
authors.initials: S
authors.lastname: Naegel
authors.forename: Hans-Christoph
authors.initials: HC
authors.lastname: Diener
authors.forename: Zaza
authors.initials: Z
authors.lastname: Katsarava
authors.forename: Mark
authors.initials: M
authors.lastname: Obermann
mesh_terms: D000328:Adult; D001933:Brain Stem / Q000187:drug effects / Q000503:physiopathology; D002110:Caffeine / Q000008:administration & dosage*; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement / Q000379:methods; D058748:Pain Perception / Q000187:drug effects / Q000502:physiology*; D012018:Reflex / Q000187:drug effects / Q000502:physiology; D012907:Smoking / Q000503:physiopathology*; D055815:Young Adult
chemical_list: D002110:Caffeine