A Dynamical Model for the Transmembrane Potential Regulation by pH

Abstract : Three physico-chemical cell parameters have been shown by the biologists to be of importance for understanding the cell behavior: the transmembrane potential (TMP) which modifies substantially the cell functional activity, the intracellular pHi whose dynamics influences a number of other ionic fluxes and, to a lesser extent, the cell volume. In this work we present a dynamical model for understanding how the pHi influences the TMP. In this model we consider the HCO3 − /Cl− and Na+/H+ exchangers as well as the bicarbonate/carbon dioxide buffering mechanism and also the ions conductance dependence to the intracellular pHi. We show that the conductances of the ions are the most important factors that have an impact on the TMP evolution and that the intracellular pHi controls the membrane ionic conductance. Therefore, our new dynamical model support the hypothesis that pHi regulates the TMP dynamics due its influence on membrane ionic conductances.