Slow release of transmitter at the squid giant synapse.
The giant synapse of the squid was tested with small amplitude, long-lasting depolarizations applied to the presynaptic terminal. The presynaptic potential at which transmitter release could be detected was only a few millivolts more positive than the resting potential, and much less positive than the 'threshold' for transmitter release by a brief (<1 msec) depolarizing pulse. Onset and termination of this low-level release were very slow.
Charlton
M P
MP
Department of Zoology, University of Toronto, Toronto, Ont. Canada.
Atwood
H L
HL