Measurement of pre- and post-synaptic proteins in cerebral cortex: effects of post-mortem delay.
Assessments of synaptic density in human brain are often based on measurements of synaptic proteins. Little information is available on their post-mortem stability. We have investigated this by ELISAs of the pre-synaptic proteins syntaxin and synaptophysin, and the post-synaptic protein PSD-95, in rat and human cortex. The rat brains were cooled in situ from 37 to 20 or 4 degrees C over 3 h, and then kept at 20 or 4 degrees C for a further 24-72 h, to simulate post-mortem storage at room temperature or in a mortuary refrigerator. Synaptophysin and PSD-95 levels in rat cerebral cortex were not significantly decreased after 72 h of incubation at 20 degrees C. Syntaxin was stable for 24 h but decreased by 39-44% at 48-72 h. Storage at 4 degrees C resulted in a similar reduction of syntaxin levels over 72 h. In human brain tissue from 160 people aged 24-102 years, post-mortem delay had little effect on synaptic protein levels in superior temporal cortex, but was associated with a decline in PSD-95 and syntaxin in mid-frontal cortex after 24 h. The more robust stability of synaptophysin may be related to its multi-transmembrane structure.
Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology (Care of the Elderly), University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK.
Lai Khai
LK
Siew
Seth
S
Love
David
D
Dawbarn
Gordon Keith
GK
Wilcock
Shelley Jane
SJ
Allen
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002540:Cerebral Cortex / Q000737:chemistry* / Q000378:metabolism / Q000473:pathology; D000076122:Disks Large Homolog 4 Protein; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000032:analysis* / Q000378:metabolism; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000032:analysis* / Q000378:metabolism; D011180:Postmortem Changes; D050765:Qa-SNARE Proteins; D051381:Rats; D013569:Synapses / Q000737:chemistry* / Q000378:metabolism; D016708:Synaptophysin / Q000032:analysis* / Q000378:metabolism; D013997:Time Factors
D000076122:Disks Large Homolog 4 Protein; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050765:Qa-SNARE Proteins; D016708:Synaptophysin; C033652:postsynaptic density proteins