The influence of local cooling on neuromuscular transmission in the myasthenic syndrome of Eaton and Lambert.

The effect of local cooling was studied in two patients with the Eaton-Lambert syndrome. We stimulated the ulnar nerve and registered the compound muscle action potential, the twitch force, and the maximum tetanic force. A distinct improvement of neuromuscular transmission occurred after cooling. The amplitude of the muscle action potential and the twitch force were larger and the time of the postactivation facilitation was longer. This effect of cooling is similar to the effect of guanidine on neuromuscular transmission. The release of acetylcholine at the nerve terminal is probably enhanced by cooling.