Abstract
The ureter of guinea pig was stimulated by the rectangular pulse, and the effect of stimulation was detected by the appearance of the action potential as an indicator.
Relation between the voltage of rectangular pulse and excitation time (t) was favored of Weiss's experimental formula. The values of chronaxie were 18 msec and 22 msec, which were considerably longer than that of nerve or skeletal muscle fiber. But if the values of respective chronaxie were adopted as the unit of excitation time, the V-t relation of ureter was similar to other excitable tissues. There is no essential difference in the process of excitation among those tissues.
But the excitability is not the same along the entere length of the ureter. V-t relations are different from part to part along the ureter. It is supposed, as the results, the velocity of the propagation of action potential is not constant along the ureter, and that fact was proved experimentally.
The strength of action potential at the stimulated part is weak, however it grows up to its full strength in the way of proagation.
The true latency which means, according to the present author, the time from the end of the excitation time to the appearance of action potential at the stimulated part, was measured. The true latency was several hundred msec.
If the voltage of the stimulating current is kept at constant, the true latency shortens depending on the duration of the current. Relation between the true latency and the duration of stimulating current is hyperbola, and is favor of Weiss's experimental formula.
