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Axons: isolation from mammalian central nervous system
Abstract:
Centrifugation of a homogenate of white matter, in a solution of buffered sucrose containing salt, produces a floating layer of myelinated axons. When these are suspended in hypotonic buffer, the mnyelin swells and strips away from the axon. Axons are then separated from the myelin by centrifugation. The resulting preparation consists of a variable population of processes with lengths up to 200 micrometers and diameters between 0.3 and 5.0 micrometers. The axons contain neurofilaments and mitochondria, although no axolemma or neurotubules are evident. The preparation contains cerebroside and sulfatide, yet is essentially free of myelin.
Insights
Researchers isolated pure axons from white matter. This method removes myelin, yielding axon preparations suitable for studying axonal components like neurofilaments and mitochondria.
Area of Science:
- Neuroscience
- Biochemistry
- Cell Biology
Background:
- White matter consists of myelinated axons, crucial for nerve impulse transmission.
- Understanding axonal components requires pure axon preparations, free from myelin sheath.
Purpose of the Study:
- To develop a method for isolating pure axons from white matter.
- To characterize the biochemical and structural components of isolated axons.
Main Methods:
- Homogenization of white matter in buffered sucrose solution.
- Separation of myelinated axons via centrifugation.
- Swelling and stripping of myelin in hypotonic buffer.
- Final isolation of axons through differential centrifugation.
Main Results:
- A distinct layer of myelinated axons was obtained.
- Myelin was effectively removed, yielding axon preparations.
- Isolated axons ranged from 0.3-5.0 micrometers in diameter and up to 200 micrometers in length.
- Axons contained neurofilaments and mitochondria, but lacked axolemma and neurotubules.
- The preparation was rich in cerebroside and sulfatide, with minimal myelin contamination.
Conclusions:
- This centrifugation-based method successfully isolates pure axons from white matter.
- The resulting axon preparations are suitable for investigating axonal structures and biochemical composition.
- The absence of myelin and presence of specific organelles provide insights into axonal integrity.