Key points are not available for this paper at this time.
Abstract 1. The effect of brief depolarizations focally applied to a motor nerve ending was studied. Particular attention was paid to the relation between (i) strength and duration of the pulse and (ii) the size and latency of the resulting end-plate potential. 2. The release of acetylcholine lags behind the depolarization which causes it. If pulses of less than 4 ms duration are used (at 5 °C), the release starts after the end of the pulse. 3. Within a certain range, lengthening the pulse increases the rate of the ensuing transmitter release. 4. Unexpectedly, lengthening the depolarizing pulse also increases the latency of the transmitter release. This finding is discussed in detail. It is regarded as evidence suggesting that entry into the axon membrane of a positively charged substance (external Ca2+ ions or a calcium compound CaR+) is the first step leading to the release of acetylcholine packets from the terminal.
Katz et al. (Tue,) studied this question.