Neurotropin inhibits axonal transport in cultured mouse dorsal root ganglion neurons.

Axonal transport is a basic neuronal cell function and important for the supply of materials that maintain neuronal cells, and any increase or decrease in axonal transport expresses the state of neurons. Neurotropin is an analgesic agent commonly used for the treatment of chronic pain, but its mechanism of action remains not fully understood. The effects of neurotropin have been investigated in various animal models of nerve injury and chronic pain. In the present study, we dissected the effects of neurotropin on sensory neurons with a special focus on axonal transport using cultured mouse dorsal root ganglion (DRG) neurons. Movement of organelles in neurites was recorded by real-time video-enhanced microscopy. Neurotropin significantly reduced bidirectional axonal transport in time- and concentration-dependent manners without affecting the diameter of these neurites. This is the first report to show the inhibitory effect of neurotropin on axonal transport, and suggest that this action may mediate, at least in part, the analgesic effects of this agent.