Effect of vecuronium on the release of acetylcholine after nerve stimulation

To the Editor: The recent article by Naik et al. (8) suggests that during a brief tetanic contraction of skeletal muscle, a vasoactive substance is released that results in vasodilation and thus contributes to the rapid increase in blood flow after the muscle contraction. The authors concluded that the acetylcholine released from the motor nerve ending in response to nerve stimulation is not this vasoactive substance, as muscle blood flow did not change in response to nerve stimulation during neuromuscular blockade. The neuromuscular blockade was produced by vecuronium bromide, which was assumed to have no effect on the release of acetylcholine in response to nerve stimulation.