PROPERTIES OF NERVE AXONS (I) MOVEMENT OF SODIUM AND POTASSIUM IONS DURING NERVOUS ACT IV ITY

Experiments with the giant nerve fibres of squids and cuttlefish show that electrical activ-ity is associated with characteristic movements of the sodium and potassium ions. When an im-pulse is conducted along one of these fibres sodium ions move inwards from the more concen-trated solution outside the fibre while potassium ions move outwards from the more concentrated solution inside the fibre. Measurements with tracers, such as those made by Rothenberg (1950), Keynes (1951), Keynes and Lewis (1951