Effects of intraneural injection of taxol on retrograde axonal transport and morphology of corresponding nerve cell bodies

Taxol exerts a potent effect on the assembly and stability of cellular micro tubules. In the present study this drug was injected into the facial nerve of mice, and its influence on retrograde axonal transport and on morphology of the facial nerve cell bodies was monitored. A reduction in the amount of retrogradely transported fluorescein isothiocyanate-conjugated wheat germ agglutinin from the peripheral field of innervation to neuronal perikarya was demonstrated by cytofluorometry. Transport was not completely blocked, since some degree of tracer accumulation was found in most neurons. Morphometric analysis was employed to determine the volume fraction of cells and cell nuclei as well as nucleolar size on micrographs of the facial nucleus. After facial nerve transection the reaction in nerve cell bodies was similar in taxol-injected animals and in animals not exposed to this substance. Furthermore, intraneural injection of taxol without prior nerve section resulted in nucleolar enlargement. The present data show that taxol-induced disturbances in microtubule organisation interferes with the retrograde axonal transport and suggest that changes associated with the retrograde nerve cell reaction may develop when the transfer of material from the peripheral field of innervation is disturbed.