Ionic channels in nerve membranes, 50 years on.

Abstract This retrospective traces the hypothesis of ion channels from an early statement in a 1970 essay in this journal (Hille, B., 1970, Prog. Biophys. Mol. Biol. 21, 1–32) to its realization today in biophysical, molecular, biochemical, and structural terms. The Na+ and K+ channels of the action potential have been isolated, reconstituted, cloned, mutated, and expressed. Refined atomic structures of several conformational states are known. The discoveries over this half century history illustrate the growth of a field from initial ideas to a mature discipline of biology, physiology, and biomedical science.