抄録
1. Method was described for isolating and recording extracellularly a functionally single unit activity from the coccygeal lymph-heart of toad in spontaneous activity.
2. The single unit activity produced for an individual systole of the organ was composed of 3 to 5, most frequently, of 4 simple components, which were slow junctional potentials in nature, successively superposing on preceding ones, but without initiating any muscle impulse.
3. The component, the junctional potential which was able to be produced by stimulation to the root, was analo ous to the intracellular record obtained in the previous report, and also similar to s. j. p.in the skeletal muscle.
4. Conduction rate was determined on the nerve fibers which were responsible to the single unit activity. And at the level of the XIth ventral root, the rates ranged from 6 to 14m/sec which might fall in the boundary between those of the large-and small-nerve fibers in the skeletal muscle.
5. Mechanogram of the systoles of the organ was recorded with a calibrated mechano-transducer, simultaneously with the electrical activity. Each of the systoles showed a dome-like configuration of about 0.5sec and 0.3sec in duration at the levels of 10% and 50% of their maximum height. Complete relaxation took about 0.3sec after cessation of nerve volleys.
These findings were discussed especially in terms of the properties of the slow-muscle system in skeletal musculature in toad.
