Axoplasmic transport with velocities induced by pargyline

Abstract

The axoplasmic transport of proteins in spinal motor neurons is altered by pargyline, a drug that causes increased release of monoamines. Two new peaks of transported protein were detected in the sciatic nerves of rats treated with pargyline (75 mg/kg/day ip for three days). These peaks moved with velocities of 595 mm/day (peak I) and 1,230 mm/day (peak II). The bulk of labeled protein was still transported at the control rate of 362 mm/day. Electrophoresis of transported polypeptides labeled with [35S] methionine showed that peak I material was qualitatively similar to material transported at the normal rate in controls, but peak Ii material contained fewer labeled polypeptides. Both peak I and peak II differed from controls in the relative intensity of labeling of various polypeptides. Fast axoplasmic transport in sensory neurons was unaffected by pargyline. Intraspinal injection of pargyline (50 microgram/day for three days) caused changes in axoplasmic transport similar to those induced by intraperitoneal pargyline. These results show that transport of certain proteins along a peripheral nerve can be accelerated by a mechanism initiated in the region of the nerve cell bodies.