TEMPERATURE-DEPENDENCE OF CONDUCTIVITY IN ELECTROLYTE-SOLUTIONS AND IONIC CHANNELS OF BIOLOGICAL-MEMBRANES

Temperature is a key parameter in the description of any physical syst em. Experimental study of the temperature dependence of conductivity i s very valuable in building and testing theoretical models. This fact does not appear to be fully appreciated and exploited in the study of ionic channels of biological membranes owing in part to the lack of an adequate theory for the temperature dependence of conductivity in ele ctrolyte solutions. To redress this imbalance, and to encourage furthe r temperature-dependence studies in ionic channels, we first give expl icit expressions for the conductivity of ions in electrolyte solutions in terms of the microscopic parameters of the liquid. We then propose that the dynamics of ion transport in membrane channels are similar t o that in bulk electrolyte solutions, except that ions permeating the pore need to surmount a potential barrier, the height of which can be deduced experimentally. Finally, we use our model to analyze the condu ctance-temperature relationships obtained in two types of single ionic channels.