Optimal fixation of chick synaptosomes using different osmotic pressures.

Chick synaptosomes were found to remain intact following fixation in the presence of 0.2 M sucrose or 0.3 M sucrose. Increasing the sucrose concentration up to 0.4 M significantly decreased the number of intact synaptosomes; however, typical intrasynaptosomal organelles such as synaptic vesicles and mitochondria were visible in all preparations. This work suggests possibly important species differences in synaptosomal structure between chick and rat synaptosomes.