A target theory description of the chemical inactivation of membrane functions

The basic ideas of target theory (currently employed in radiobiology) are applied to describe the chemical inactivation of any biological function arising from the summation of a large number of identical individual contributions. A general equation giving the fractional survival of a biological activity as a function of the mean number of hits received by each target from the inactivating molecules and on the number of individual targets forming the functional assemblies is established. It properly accommodates phenomena as diverse as the decrease by anesthetics of the compound action potential in nerve trunks, the inhibition by protein cross-linking reagents of the active transport of sodium across epithelia and the killing of bacteria by disinfectants. This approach seems able to extract molecular level information from macroscopic data.