Comparative biochemical and biophysical studies on rat brain synaptosomes.

1. Introduction tosomal fractions was also checked by electron microscopy. Synaptosome isolation methods should meet two principal but contradicting requirements: The fraction should be enriched as much as possible in synap tosomes, while the amount of time used during the isolation process should be as short as possible. The conditions of synaptosomal preparation and the duration of each step of purification greatly affect the physiological state of the subcellular fractions. In some biochemical and biophysical examinations of synaptic activities the surveyor needs information about the state of the electrogenic mechanism. Several procedures are available to measure the membrane potential in suspension as a physiological parameter of the synaptosomes. Some of these methods are based on the distribution of radioactive isotopes [ 1,2] while others utilize specific, potential-sensitive dyes [3,4].