Molecular Pharmacology, Vol 19, 291-294, Copyright © 1981 by the American Society for Pharmacology and Experimental Therapeutics

Effects of Mitosis Inhibitors on Respiration and Fast Axonal Transport in Frog Sciatic Nerves

¹ Department of Zoophysiology, University of Lund, Lund, Sweden

The effects of mitosis inhibitors on fast axonal transport of ³H-labeled proteins and ¹⁴CO₂ production from radioactive glucose were studied in vitro. Colchicine and lumicolchicine depressed respiration to the same extent but only the former inhibited axonal transport. Nocodazole had effects similar to those of colchicine, whereas podophyllotoxin affected only transport. A stimulation of respiration was found with vinblastine at transport-inhibitory concentrations. None of the drugs affected protein synthesis in the dorsal ganglia or the amplitude and propagation of the compound action potential. The results do not suggest a close coupling and feedback between axonal transport and respiration. Alternatively, the energy requirements of axonal transport are too small to be detectable with the present system. The drug-induced changes in respiration were probably not caused by effects on motility-related functions of microtubules and were not sufficient to depress or stimulate two other energy-requiring processes, protein synthesis and electrical activity.