抄録
1. The behavior of the isolated sartorius muscle of the frog in calcium-deficient medium has been studied by recording the transmembrane potentials of adjacent two fibers simultaneously.
2. Accompanied with rise and fall of the educed fibrillation, the adjacent fibers exhibited different grades of electrical activity, but most of their activity appeared synchronized in rhythm particularly at the crest of fibrillation.
3. A few different types of small waves were recorded during the spontaneous activity; the slow rising depolarization preceding spike potential (pacemaker-like potential), the small fast wave with short duration produced by electrotonic spread of action current of the neighboring fiber (interaction potential), and the long slow wave of unknown origin.
4. The interaction potentials were mostly positive (depolarization) but sometimes negative (hyperpolarization) or diphasic as expected, appearing in two or three rhythms simultaneously and piling up on each others.
5. Mechanisms of the fibrillation were discussed obtaining a conclusion that some fibers, acting as pacemakers, were excited spontaneously and the excitation was transmitted to adjacent fibers through low-safety-factor, intercellular, electrical connections.
Cordial thanks are due to the Rockefeller Foundation for the contribution of many equipments used in this experiment.
