The effect of asphyxia on the mechanical response of the frog’s unstriated muscle and its relation to tonus

Abstract

1. Asphyxia at first increases the response of frog’s unstriated muscle; this is followed by diminution and then paralysis. These effects are also produced by cyanide. This increase in excitability is not abolished by iodoacetic acid. 2. Asphyxiai arrest is relieved by glucose, potassium and the other substances that produce tonic contraction. 3. In the presence of oxygen the muscle becomes hyperirritable in acid solutions and so possesses different aerobic metabolic mechanisms in alkaline and acid solutions respectively. 4. In acid solutions, pH 6, sodium lactate, acetate and propionate improve the response to alternating current. 5. Asphyxia does not produce rapid arrest of movement in muscle poisoned with iodoacetic acid. 6. In a muscle poisoned with iodoacetic acid, then exhausted by frequent stimulation in asphyixia, and then revived by oxygen, sodium lactate and sodium butyrate improve the response. Glucose, glycine, sodium acetate and propionate have no effect. 7. In asphyxia, tone at first decreases and then increases; this asphyxiai contraction is identical with tone that does not use oxygen.