A calcium dependent link beyond the electrical excitation of the membrane in muscular contraction

Effects of Reducing the Extracellular Calcium Concentration on the Resting Potential of Frog's Skeletal Muscle Fibers

“…Moreover, the large fall in resting potential (> 20 mV) in the absence of extracellular calcium ions seems to occur only in amphibian and possibly mammalian (EDMAN and GRIEVE, 1963b) skeletal muscle. Removal of extracellular calcium ions in vitro does not alter the membrane resting potentials of striated muscles from crayfish (ZACHAROVA and ZACHAR, 1967) or lobster (GAINER, 1968) and causes only a small fall in resting potential (usually about 4 mV) in squid axons (FRANKENHAEUSER and HODGKIN, 1957) or in myelinated nerve fibers (STAMPFLI and NISHIE, 1956;FRANKENHAEUSER, 1957).…”

“…However, in other "later" experiments excitability remained and presumably the resting potential was not greatly reduced under the same conditions. Subsequently, many other investigators have reported large reductions (> 20 mV) in the intracellularly recorded resting poten-tials of amphibian muscle fibers kept in calcium-free Ringer solution (ABOOD et al, 1963;EDMAN and GRIEVE, 1962, 1963a, 1963b, 1964JENDEN and REGER, 1963;KOKETSU and NODA, 1962;LUTTGAU, 1963) or calcium-free choline-Ringer solution (CURTIS, 1963).…”