The article by Whittaker, Michaelson, and Kirkland describes the separation of synaptic vesicles from nerve-ending particles, known as synaptosomes. Synaptosomes are discrete particles derived from brain tissue that retain the structural features of nerve endings. They can be isolated using differential and density-gradient centrifugation and contain significant amounts of particle-bound acetylcholine, choline acetyltransferase, hydroxytryptamine, and noradrenaline. The authors propose that these substances represent acetylcholine and its metabolic enzymes localized within synaptosomes derived from cholinergic neurons. The synaptosomes exhibit a complex fine structure when examined under an electron microscope, consisting of thin-walled bags containing synaptic granules or vesicles, mitochondria, and thickened regions of the post-synaptic membrane. The study also explores the disruption of synaptosomes to obtain synaptic vesicles, intraneuronal mitochondria, external and postsynaptic membranes, and soluble constituents for biochemical and pharmacological analysis. The authors compare their methods with those of De Robertis et al., arguing that their preparations are more homogeneous and less contaminated with small membrane fragments and intact synaptosomes. The results highlight the separate localization of acetylcholine, choline acetyltransferase, and cholinesterase within the synaptic region, suggesting multiple compartments for acetylcholine in nervous tissue. The yield of isolated synaptic vesicles is estimated to be low, but the authors continue to work on improving the isolation process.The article by Whittaker, Michaelson, and Kirkland describes the separation of synaptic vesicles from nerve-ending particles, known as synaptosomes. Synaptosomes are discrete particles derived from brain tissue that retain the structural features of nerve endings. They can be isolated using differential and density-gradient centrifugation and contain significant amounts of particle-bound acetylcholine, choline acetyltransferase, hydroxytryptamine, and noradrenaline. The authors propose that these substances represent acetylcholine and its metabolic enzymes localized within synaptosomes derived from cholinergic neurons. The synaptosomes exhibit a complex fine structure when examined under an electron microscope, consisting of thin-walled bags containing synaptic granules or vesicles, mitochondria, and thickened regions of the post-synaptic membrane. The study also explores the disruption of synaptosomes to obtain synaptic vesicles, intraneuronal mitochondria, external and postsynaptic membranes, and soluble constituents for biochemical and pharmacological analysis. The authors compare their methods with those of De Robertis et al., arguing that their preparations are more homogeneous and less contaminated with small membrane fragments and intact synaptosomes. The results highlight the separate localization of acetylcholine, choline acetyltransferase, and cholinesterase within the synaptic region, suggesting multiple compartments for acetylcholine in nervous tissue. The yield of isolated synaptic vesicles is estimated to be low, but the authors continue to work on improving the isolation process.