| Abstract: | The "semi-excitation" is an excitation (like phenomenon) found by the authors, first in ENM and then in nerve during observation of the action potential and impedance decrease associated with excitation. The phenomenon was further investigated in relation to the action potential and impedance decrease (for AC of 13 kHz) of the stimulated site on the sciatic nerve and ENM. The nature of the phenomenon was the following. 1. The configuration of the action potential and impedance decrease were almost the same as that of the (complete) excitation, but the durations of the potential change (plateau) and impedance decrease depended on entirely to the duration of stimulating current. 2. Submaximum amplitude of action potential and impedance decrease were graded by the intensity of the stimulating current, but the threshold of this excitation was found. 3. During or after the semi-excitation, absolute or relative refractory period was not found. 4. Both in nerve and ENM, transition from complete excitation to semi-excitation or vice versa was observed. 5. Semi-excitation was found to occurr in the state of reduced membrane potential of the nerve and ENM. |
