Preparation of synaptosomes, neuromelanin granules and synaptic vesicles

1. Synaptosomes Kiebler et al [1] was the first group to describe the use of a discontinuous iodixanol gradient in the isolation of dendritic spines from mouse hippocampus. The gradient comprised four layers of 9%, 12.5%, 15% and 25% (w/v) iodixanol (equivalent to densities of 1.076, 1.095, 1.105 and 1.152 g/ml); the densest solution contained the material pelleted from the hippocampal homogenate at 900 g for 10 min. The gradient was centrifuged at 18,000 g for 20 min and it was described as a velocity flotation separation. The primary aim of the gradient was to isolate dendritic spines and the material that banded at the 9%/12.5% interface was further fractionated in a secondary Percoll-sucrose gradient.