Factors required for calcium dependent acetylcholine release from isolated torpedo synaptic vesicles

The release of acetylcholine (Ach) from Torpedo synaptic vesicles has been investigated. Factors have been found which induce Ca⁺² dependent Ach release from the synaptic vesicles. In the absence of these factors, the vesicles are not affected by Ca⁺². Addition of a soluble factor to the vesicles induces a Ca⁺²-dependent release of their Ach. This secretion is enhanced by a non-vesicular membranous component which, by itself, does not induce the Ca⁺²-dependent release. These results demonstrate that vesicular Ach release may be studied in vitro and thus will enable the study, at the molecular level, of the biochemical events underlying neurotransmission.