DISCONTINUOUS VOLUME TRANSITIONS INDUCED BY CALCIUM SODIUM-ION EXCHANGE IN ANIONIC GELS AND THEIR NEUROBIOLOGICAL IMPLICATIONS

Discontinuous volume transitions in poly(acrylic acid) gels were studi ed by determining equilibrium swelling curves of small gel beads immer sed in salt solutions containing varying concentrations of Ca2+ and Na +. Reversible contractions of gel membranes associated with Ca2+-Na+ e xchange were examined using both isometric and isotonic recording devi ces. A discontinuous change in electric conductance was demonstrated i n association with Ca2+-Na+ exchange in gel membranes. These experimen tal findings provide a sound physicochemical basis for elucidating the mechanism of nerve excitation. (C) 1994 John Wiley & Sons, Inc.