Effects of nicotine gum on F waves in non-smokers

The effects of chewing gum, containing 0 and 4 mg nicotine, on F waves were studied in healthy volunteers in a repeated measure design. F responses were recorded from the abductor pollicis brevis muscle following stimulation of the median nerve at the wrist. The persistence and various amplitude measures were analysed. Chewing a 4 mg nicotine gum, with a considerable rise in systemic nicotine (6.4-37.4 ng/ml), failed to produce significant effects on F wave parameters in relation to the placebo baseline. The analysis of different F wave amplitude ranges, however, revealed significant nicotine-induced changes: a dose-related decrease of F responses > or = 500 microV and an increase of F waves between 200-290 microV. This may be due to an activation of Renshaw cells in the spinal cord.