English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Keynes' and many other investigators considered that the ratelimiting process of the membrane excitation was probably the conformation change of the membrane molecules rather than the diffusion of ions across the membrane. The purpose of the present paper is to examine to what extent the diffusion process contributes the rate of the electrophysiological change of the membrane. The viscosity of the external and the internal solutions of the intracellularly perfused squid giant axon was changed by adding non-electrolytes to solutions. As reported previously, the resultant increase in the osmotic pressure did not cause any damage to the axon when the osmolarities of the external and the internal solutions were equal.2~ It was found that the time course of the action potential was prolonged in proportion to the increase of the viscosity of solutions. A hindmost stellar giant axon of squid (Doryteuthis bleekeri) was used. The intracellular perfusion technique was the same as that previously reported.3~ A whole system was kept at 10-15°C. Current stimuli were supplied by a platinized platinum wire electrode and the membrane potentials were recorded by a capillary electrode filled with 0.6 M KC1-agar. The viscosity of solutions was raised by increasing the concentration of neutral solutes, i.e., glycerol, glucose and sucrose. Molarities of electrolytes were kept constant. External solutions contained 450 mM NaCI and 100 mM CaC12 and internal solutions contained 100 mM KF. The resistivity of solutions was measured with a usual conductivity bridge. Fig. 1 illustrates typical space claimped action potentials in viscous glucose solutions. The time course of the action potentials was prolonged as the viscosity of solutions was increased by raising the concentration of glucose. We used the resistivity instead of the bulk viscosity as the measure of the interaction between ions and viscous solvents, since the microscopic viscosity which is important to the ionic diffusion is different from the bulk viscosity.4> For the

Prolongation of the Action Potential of Squid Giant Axons in Viscous Solutions