[Mechanisms of prolonged action potential generation in barium solutions]. / Mekhanizmy generatsii prodlennykh potentsialov deistviia v barievykh rastvorakh.

The membrane currents were recorded under voltage clamp from identified nerve cells of the Helix pomatia. The replacement of the external Ca ions in normal solution by Ba ions produced a shift in the potassium conduction-voltage curve along the voltage axis in the positive direction. The decrease in the limiting value of the potassium conduction was also observed. In Na-Ca-free solutions containing Na ions but no other divalent cations the inward membrane current was recorded. This current was separated into two components: an early fast inactivating (I) and a smaller long lasting component (II). It seems that the prolongation of the action potential in barium solution is due to the suppression of K conduction by Ba ions and to the existence of the long-lasting inward current.

[Propagation of the action potential in the vicinity of the soma of giant neurons after the Hodgkin--Huxley model]. / Issledovanie rasprostraneniia potentsiala deistviia vblizi somy gigantskogo neirona na modeli Khodzhkina--Khaksli

The Hodgkin--Huxley equations were used to investigate the loading effect of somatic membrane on spike generation in an axon. The depression of the amplitude of antidromic spike near the soma is demonstrated. It is shown that direct activation of the neuron by a current pulse through an intracellular electrode inserted in the soma causes the spike origination in the axon rather far from the cell body because of the loading effect. An increase in the magnitude of the current pulse causes a shift of the site of spike initiation towards the soma.