Block of axoplasmic transport in vitro by vinca alkaloids

The three potent antimitotic vinca alkaloids: vincristine (VCR), vinblastine (VLB), and vindesine (VDS) were compared for their effect in blocking axoplasmic transport in vitro using a desheathed preparation of the peroneal branch of cat sciatic nerve. A range of vinca alkaloid concentrations from 1-100 microM was examined. The relative order of potency in blocking axoplasmic transport was VCR greater than VLB greater than VDS at a concentration of 25 microM. At the higher concentrations block occurred so rapidly that a statistically significant difference between these agents could not be obtained. The relation of vinca block to the transport mechanism is discussed.