Abstract
When 2 cc. of 1% sodium bicarbonate is injected intraperitoneally in frogs there results, in about one-half hour, a disorder of the skeletal muscles characterized by fascicular twitching and dystonic movements. This was described as tetany by Ringer 1 in 1884. A similar condition develops about one-half hour after the intraperitoneal injection of 2 cc. of a neutral 5% solution of sodium phosphates. We have not been able to produce this type of reaction by administration of sodium oxylate, sodium fluoride, potassium chloride, calcium chloride, magnesium chloride, ammonium chloride or hydrochloric acid, even when these substances were given in doses large enough to cause complete prostration.
We have studied the effect of all of these substances on the fatigue curve of the isolated gastrocnemius of the frog. The muscle was stimulated directly through silver chloride electrodes with faradic shocks delivered at the rate of 3 makes and breaks per second. Care was taken to have the stimuli always the same and strong enough so that the make shocks gave maximal contractions. The normal muscle when stimulated in this way responds at first with discrete contractions returning to the base line. After 15 or 20 seconds relaxation becomes delayed and fatigue contracture slowly develops resulting in a steadily maintained contracture of approximately the same height as the original discrete contraction.
A muscle from a frog treated with a neutral solution of sodium phosphates responds in a very different manner. Even after the first contraction, relaxation is much delayed and the muscle remains shortened with contractions of small magnitude superimposed upon the contracture curve. When the stimulation is discontinued, relaxation is slow and imperfect.
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