Neurotransmitter release from viable purely cholinergic Torpedo synaptosomes

Viable synaptosomes from the electric organ of Torpedo have been prepared and partially purified. The synaptosomes contain about 100 fold more acetylcholine (Ach) than do mammalian synaptosomes, synaptic vesicles and mitochondria. The Torpedo synaptosomes release Ach by K depolarization in the presence of Ca ions, and manifest an ionophore-mediated Ca-dependent Ach release. These results demonstrate that the synaptosomes contain the neurosecretion apparatus in a functional viable state. Since this preparation uniquely contains only one neurotransmission system (cholinergic), it is most suitable for structural and functional investigations of neuro transmission.