[Electron microscopic cytochemical and morphometric study of the cerebral cortex synapses in postmortem autolysis]

Area of Science:

• Neuroscience
• Cell Biology
• Histology

Background:

• Synaptic integrity is crucial for neuronal function.
• Understanding postmortem changes in brain tissue is vital for research accuracy.
• Neurofilaments play a key role in synaptic structure and function.

Purpose of the Study:

• To investigate the timeline and characteristics of synaptic autolysis in the rat cerebral cortex postmortem.
• To examine neurofilament accumulation and its relationship with synaptic degradation.
• To differentiate autolytic processes in mature versus immature synapses.

Main Methods:

• Brain tissue staining using phosphotungstic acid.
• Microscopic examination of the molecular layer of the rat cerebral cortex.
• Assay of neurofilament accumulations in synapses.
• Observation at various postmortem intervals (30 min, 90 min, 6 hours).

Main Results:

• Autolysis initiated in the dense projections of the presynaptic grid.
• Synaptic autolysis was observed in both mature and immature synapses within 30 minutes.
• By 90 minutes, autolysis was significantly enhanced in asymmetric synapses.
• After 6 hours, autolysis extended to involve mature and indefinite synapses.

Conclusions:

• Synaptic autolysis begins rapidly after death, affecting various synapse types.
• The progression of autolysis varies between synapse types and maturation stages.
• Phosphotungstic acid staining effectively visualizes postmortem synaptic degradation and neurofilament changes.