Direct comparisons of synaptic functional parameters in brain tissues from different groups of experimental animals and different samples from post mortem human brain are often hindered by the inability to perform assays at the same time. To circumvent these difficulties we developed methods for cryopreservation and long-term storage of neocortical synaptosomes. The synaptosomes are suspended in a cryopreservation medium containing 10% dimethylsulfoxide and 10% fetal bovine serum, and are slowly cooled to - 80°C and then stored in liquid nitrogen. The function of plasma membrane glucose and glutamate transporters, and mitochondrial electron transport activity and membrane potential were measured in fresh, cryopreserved (CP), and non-cryopreserved freeze-thawed (NC) synaptosomes. Glucose and glutamate transporter activities, and mitochondrial functional parameters in CP synaptosomes were essentially identical to those in fresh unfrozen synaptosomes. Glucose and glutamate transport were severely compromised in NC synaptosomes, whereas mitochondrial function and cellular esterase activity were largely maintained. Electron paramagnetic resonance studies in conjunction with a protein-specific spin label indicated that cryopreservation did not alter the physical state of synaptosomal membrane proteins. These methods provide the opportunity to generate stocks of functional synaptosomes from different experiments or post mortem samples collected over large time intervals.
|Number of pages
|Brain Research Protocols
|Published - Sep 1998
Bibliographical noteFunding Information:
This work was supported by grants to M.P.M. from the NIH (AG14554, AG05119 and AG05144) and to D.A.B. from the NIH (AG10836 and AG05119).
- Cerebral cortex
- Electron paramagnetic resonance spectroscopy
- Excitatory amino acid
- Mitochondrial respiration
ASJC Scopus subject areas
- Neuroscience (all)