抄録
The recovery curve of excitability that follows an excitation in smooth muscle of the ureter of guinea-pig is examined. The responses such as action potentials and contractions of muscle recover earlier than the conduction velocity. In spite that the contraction curve has summation when a test shock is given in the relative refractory period, no action potentials are recorded from the leading electrode which is placed about 7mm. far from the stimulating point. When the excitability recovers slightly, the small slow potential change is recorded and after the complete recovery normal pattern of action potential is obtained. This fact shows that the excitation is conducted decrementally in smooth muscle when that muscle is in the state of refractoriness. Also from the patterns of action potentials recorded at several stages of relative refractory period, it was assumed that the excitation is conducted from cell to cell through protoplasmic bridges by the electrical variation. This variation is characterized by a slow potential wave. The effects of acetylcholine, adrenaline, histamine and pilocarpine on the patterns of action potentials are also examined.
