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JE Wolf, GB Arden; The Alcohol EOG and the Underlying Components . Invest. Ophthalmol. Vis. Sci. 2002;43(13):1825.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Alcohol causes the same EOG changes as light, and we have previously shown that this change is independent of light, but operates on the same RPE mechanisms affected by light. We have determined the separate dose-response relationship of positive and negative voltage changes caused by ingestion of alcohol. Methods: Standard EOG recording techniques were used. 7% w/v alcohol was given by mouth to dark-adapted subjects who had fasted for more than 12 hours. Recordings continued for 35 minutes after drinking alcohol, so both the positive peak and the later negative trough can be well characterised. Doses range from 3.54 mg/Kg to 450 mg/Kg. Experiments were carried out on 3 normal subjects, 4th - 8th decade. Results: Simple dose response curves were obtained for both positive and negative components. The results fit the hypothesis that the voltage change is determined by the relation: [EtOH] * [R] <=≷ [EtOH.R], where <=≷ represents a reversible reaction, with forward and backward rate constants k1 and k2. For the positive peak, semisaturation occurs at a mean of 0.07g/Kg EtOH. For the negative trough it is smaller, 0.004 g/Kg. The blood concentrations causing the change can only be determined by back extrapolation from the higher doses, and is micromolar or less. Conclusion: This additional quantification re-inforces our previous conclusion (ARVO abstracts 2001) that there are at least 2 different mechanisms responsible for the positive and negative voltage changes of the alcohol EOG, and therefore it seems improbable that the human EOG is a single "damped oscillation". Also recent analysis in vitro (Rymer J. et al., Invest Ophthalmol Vis Sci 2001; 42:1921-1929) shows that several intracellular mechanisms can affect the apical and basal conductances in ways which would explain our in vivo findings.
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