Acetylcholine: fast axoplasmic transport in insect chemoreceptor fibers

Acetylcholine is transported along insect chemoreceptor axons at a rate of 12 to 13 centimeters per day after peripheral uptake of choline. Colchicine, vinblastine sulfate, and cytochalasin B all block transport, but transport continues in axons separated surgically from the cell body. These data from an insect are in accord with many studies on vertebrates which have implicated intracellular microtubules in the transport mechanism. The peripheral uptake of choline and its acetylation and transport to nerve terminals in the brain are consistent withthe suggestion that acetylcholine is an antennal sensory transmitter in insects.