Although the effects of KM on the AP amplitude or the CM were extensively studied in the past, the reports on the latency of AP is quite limited. The present study aimed to know the effect of KM upon the AP latency in relation to the AP amplitude. Twenty nine guinea pigs treated with KM were examined electrophysiologically and histologically, and following results were obtained. The initial effect of KM was the depressed AP amplitude of low signal intensity part with normal latency. In the next stage, the AP amplitude of all signal intensities was depressed with normal latency or the amplitude was depressed and the latency was prolonged in low signal intensity. The amplitude and latency in all signal intensities became abnormal in the final stage. The electrophysiological results well correlated with the histological findings.
