RESTORATION OF MEMBRANE EXCITABILITY OF SQUID GIANT-AXONS BY REAGENTS ACTIVATING TYROSINE-TUBULIN LIGASE

Using squid giant axon, an experimental survey was performed on restoration of the membrane excitability which had been partially suppressed. Among reagents examined, a combination of 400 mm KF, 50 μm tyrosine, 1 mm ATP, 1m m Mg ions and 5 μm cAMP was found to induce the restoration of the excitability to a large extent. Further addition of a small amount of either porcine brain microtubule proteins or the squid axoplasm was found to support complete restoration. The experiments suggest that tubulin-tyrosine ligase contained in the porcine brain microtubule protein fraction or the squid axoplasm maintains the coupling between cytoskeletal structures and the plasma membrane. © 1979 Springer-Verlag New York Inc.