The Open Pain Journal
2009, 2 : 71-75Published online 2009 November 5. DOI: 10.2174/1876386300902010071
Publisher ID: TOPAINJ-2-71
RESEARCH ARTICLE
Tobacco Smoking Can Potentiate C-fiber Evoked Potentials in Human Brain
2 Department of Physiological Sciences, School of life Sciences, The Graduate University for Advanced Studies,Hayama, Kanagawa, Japan;
3 Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109-0632, USA
* Address correspondence to this author at the Department of Integrative Physiology, National Institute for Physiological Sciences, 38 Nishigo-naka, Myodaiji-cho, Okazaki 444-8585, Japan; Tel: +81-564-55-7810; Fax: +81-564-52-7913; E-mail: miyazaki@nips.ac.jp
ABSTRACT
The effects of smoking and nicotine on ultralate laser evoked potentials (LEPs), the EEG responses to C-fiber stimulation by a laser beam, were investigated in humans. Ultralate LEPs were repeatedly measured in two sessions, one after smoking, and the other in abstinence from smoking. The dominant frequency of the background EEG alpha activity, heart rate and venous plasma nicotine concentration were also measured. The peak-to-peak amplitude of the two major components (N2 and P2) of ultralate LEPs was significantly correlated both with the plasma nicotine concentration and with the background alpha frequency. The results suggest an arousal effect of nicotine on C-fiber mediated pain. The effect of nicotine on C-fiber LEPs was in the opposite direction of that on Aδ fiber LEPs. The difference between C and Aδ fibers might indicate a difference in effects of nicotine on first and second pain responses.