| Nicotine, the primary addictive component found in tobacco/cigarettes, can bind to nicotinic acetylcholine receptors (nAChR), which are found throughout the central nervous system including the retina of the eye. Previous studies have shown nAChR expression in the retina of non-human and human (Hutchins & Hollyfield, 1985; Liu et al., 2009). By use of electrophysiologic measures, i.e. electroretinograms (ERGs), early reports indicated that nicotine and/or cigarette smoking affects vision and visual processing in different species (Jurklies, Kaelin-Lang, & Niemeyer, 1996; Jünemann & Damaske, 1968). Because previous human studies have used only cigarette smokers, there are questions about what role nicotine, itself, plays in vision and visual processing. Tobacco/cigarette smoke has numerous additives and chemicals that could affect measures of visual processing (Rabinoff, Caskey, Rissling, & Park, 2007). The hypothesis that nicotine administered as gum in two different dosages (2mg and 4mg) affects visual processing was tested in this study using humans with no previous smoking history. Dose-related changes were seen in measures of retinal processing, as well as, cortical processing using ERGs, flicker ERGs, and contrast sensitivity measures. To our knowledge, these studies are the first demonstration of nicotine itself having an impact on vision and visual processing in non-smokers. |
