Origin of cellular ionic currents

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Abstract
We analyze here a new mechanism leading to the spontaneous generation of endogenous ionic currents flowing in growing cells. The mechanism, based on the sensitivity of channels and pumps to membrane potential and ionic concentrations, leads to a linear instability of the uniform resting state. Ions may further or prevent the ionic currents to flow depending on the properties of the relevant pump or channel associated to them. For instance, a calcium ion can be responsible for the observed ionic disturbances. First, it contributes to favor nonuniform ionic disturbances with a wavelength of the same order of magnitude as a typical cell diameter. Second, it has the property to diffuse much more slowly in the cytoplasm than in an ordinary liquid because of the presence of negatively charged ligands. As a result, the time scale of the development of the instability in a cell of 100 μm diameter is some hours in agreement with experiments