Effect of ingestion of smokeless tobacco on motor distal latency of the median nerve

Subjects were 17 men between the ages of 18 and 32 yr. and regular users of smokeless tobacco. Each subject received three treatments consisting of one pouch of Skoal Bandits, one pinch of their regular brand, and a nonnicotine piece of chewing gum. The nervous transmission at the neuromuscular junction in the right thumb was compared before treatment and once every minute for 15 min. after treatment. Repeated-measures analysis of variance indicated a significant increase in the distal latencies for both the brand-name grouping and in the regularly used brand. No such difference was found in a control group when compared to the pretest results. It was concluded that smokeless tobacco ingestion resulted in a delay in the nervous transmission across the neuromuscular junction. This delay was hypothesized to be caused by the enduring binding action of nicotine to the acetylcholine receptor sites, thereby blocking the impulse in some of the faster conducting nerve fibers.