| Popis: |
Activation of the electrogenic sodium pump by means of increasing concentration of intracellular sodium ions in identified neurons A and B of the mollusc was followed by the hyperpolarization, decrease of the excitability, and depression of the neurons rhythmic activity. Apart from that, the amplitude and the maximal rates of rise of ascending (VB) and descending (VH) phases of action potential (AP) were almost unchanged. The depression of the electrogenic sodium pump activity due to 2,4-DNP and potassium-free medium, led to the depolarization, increase of excitability and frequency of the rhythmic activity, and decrease of AP, VB, and VH. The decrease and increase of the excitability may be explained by the changes of the critical level of depolarization. The decrease of AP, VB and VH may be accounted for by the changes of time parameters of activation and inactivation of sodium and potassium channels which are characteristic for the depolarization effect. |
