Isolation of an enriched fraction of nerve terminals from fish brain using a discontinuous Percoll gradient

A discontinuous gradient of Percoll has been used to prepare a subcellular fraction (fraction III) from fish brain which is greatly enriched in synaptic nerve endings (synaptosomes). Synaptosomes display well-preserved morphology, good functional performance as assessed by ability to release preloaded neurotransmitter following depolarization, and the fraction as a whole has an enzyme profile consistent with the presence of nerve endings. The procedure is rapid, highly reliable and provides a mean yield of 4.5 mg synaptosomes per g wet weight of brain.