Science, Vol 238, Issue 4834, 1712-1713
Copyright © 1987 by American Association for the Advancement of Science
Quantal release of transmitter is not associated with channel opening on the neuronal membrane
SH Young
and
I Chow
Department of Physiology, UCLA School of Medicine 90024.
The traditional view that quantal release of neurotransmitter results from the fusion of transmitter-containing vesicles with the neuronal membrane has been recently challenged. Although various alternative mechanisms have been proposed, a common element among them is the release of cytoplasmic transmitter, which, in one view, could occur through large conductance channels on the presynaptic membrane. Six nerve-muscle cell pairs were examined with a whole-cell patch clamp for the presence of such channels that are associated with the production of miniature end-plate potentials. Examination of the neuronal membrane current during the occurrence of 822 miniature end-plate potentials produced no evidence of large channels. Thus it is unlikely that quantal release is mediated by such channels in the neuromuscular junction.
