ATP in cholinergic nerves:evidence for the axonal transport of a stable pool

The ATP content of the cholinergic electromotor nerves of Torpedo marmorata has been measured. After freezing and thawing of pieces of nerve, their ATP content dropped rapidly to about 5% of that of pieces extracted immediately. The amount of ATP in nerves incubated in Torpedo Ringer remains at a high level over a long period. In nerves ligated for seven days there is no accumulation of total ATP above the ligature. If, however, the ligated nerves are frozen and thawed for 20 min before extraction, the residual ATP shows significant proximal accumulation at the ligature. This transport is not due to the accumulation of mitochondria at the ligature.Acetylcholine, measured in the same nerve extracts of nerve segments, is also axonally transported. The ATP which is resistant to hydrolysis is probably sequestered within a subcellular organelle. The possibility that its accumulation at ligatures may indicate movement of cholinergic synaptic vesicles which are known to contain ATP and acetylcholine is considered.