興奮膜に対する微小管の真の役割

概要

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Effects of colchicine and chaotropic anions (Cl, Br, I) on membrane excitability were examined in the squid giant axon with a mechanical stress to the axolemma altered by varying the intracellular pressure. When the intracellular pressure was kept at a high level, colchicine and chaotropic anions applied intracellularly suppressed the excitability. However, when the pressure was kept at an ambient level, these reagents did not affect the excitability for long periods of time (>1.5hr). Electron microscopic observations of the internal surface of the axolemma fixed at the high or low pressure revealed that chaotropic anions dissolved almost all cytoskeletal structures covering the membrane in a relatively short time (<0.5 -1hr). These findings indicate that removal of cytoskeletons including microtubules increases the susceptibility of the membrane to mechanical stresses. It is conclusive that microtubules per se can be a mechanical support of the membrane but they are not essentially involved in the molecular mechanism underlying electrical activities of ionic channels.
日本生物物理学会の論文