Purchase this article with an account.
Stefanie B. Varghese, Naser Naser, Tammy P. Than, Kent T. Keyser, E. Eugenie Hartmann; Effects of Nicotine on Flicker ERGs: Application of DFT and T-Circ2. Invest. Ophthalmol. Vis. Sci. 2012;53(14):5702.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To evaluate the effects of nicotine on Flicker ERGs.
Flicker ERG responses were obtained from nine healthy adult non-smokers. All individuals were evaluated as visually normal by means of a comprehensive eye exam, visual field, and color vision assessment. Subjects were tested under both control and nicotine conditions on each of two visits. The control test was administered first, and the subjects were randomly assigned to either 2mg or 4mg nicotine gum on the first visit. Subjects received the other dosage of nicotine on the second visit. Both the examiner and subjects were masked to the dosage level at both visits. ERG responses were collected using the Espion ERG system following ISCEV guidelines. Responses were recorded from one eye for each subject using a Burian-Allen lens electrode. ERGs were measured using a 540nm stimulus at a mean luminance of 30 cd.s.m-2. The stimulus was a sinusoidally flickering waveform at 100% contrast. A total of 15 recordings were obtained at frequencies between 24 and 82Hz. Flicker ERG data were analyzed using DFT and T-Circ2 analysis. Student’s t-test was used for statistical analysis. This study was approved by the UAB IRB and was in compliance with the Health Insurance Portability and Accountability Act.
Student’s t-test analysis revealed significant differences between the baseline tests for each session (p≤0.001). Therefore, further analyses were restricted to comparisons between control and nicotine conditions obtained on the same day. Both F1 and F2 amplitudes decreased with increasing flicker rate. Analysis showed a significant decrease in magnitude of F1 with 2mg nicotine (p=0.02) and no significant changes with 4mg nicotine (p=0.24) compared to baseline. Analysis of the phase delays for both F1 and F2 showed no significant changes.
Nicotinic acetylcholine receptors are expressed in neurons of non-human primate retina, primarily in the cone pathway (Liu et al. 2009). Prior studies from our lab have shown significant changes in light-adapted ERG responses with nicotine.1 The aim of this study is to further investigate the retinal level (outer vs. inner) and/or pathways on which nicotine has a larger impact. Falsini et al. (1995) have shown that the F1 and F2 of the flicker ERG are differentially affected by retinal diseases impacting different levels of the retina (E.G., F1 = AMD vs. F2 = transient retinal ischemia). Our results, thus far, indicate nicotine has a greater impact on information processing in the outer retina. It is possible that the feedback mechanisms via the amacrine cells could attribute to the greater changes seen on F1.1- Varghese, S.B. et al. (2011). The Effects of Nicotine on the Human Electroretinogram (ERG). IOVS.
This PDF is available to Subscribers Only