Biomaterial Database

Isolation and structural studies on synaptic complexes from rat brain. 1972

C W Cotman, and D Taylor

A fraction enriched in synaptic complexes has been isolated from rat brain. The major structural elements of synaptic complexes after isolation are a sector of pre- and postsynaptic plasma membranes joined together by a synaptic cleft and a postsynaptic density (PSD) located on the inner surface of the postsynaptic membrane. On its outer surface, the postsynaptic membrane has a series of projections which extend about halfway into the cleft and which occur along the entire length of the PSD. Proteolytic enzymes at high concentrations remove the PSD and open the synaptic cleft; at low concentrations the PSD is selectively destroyed. By contrast, the structural integrity of the PSD is resistant to treatment with NaCl, EGTA, and low concentrations of urea. Pre- and postsynaptic membranes also remain joined by the synaptic cleft after NaCl, EGTA, or mild urea treatment. High concentrations of urea cause the partial dissociation of the PSD. We conclude that polypeptides are probably one of the major components of the PSD and that the structural integrity of the PSD depends on polypeptides because disruption of the covalent or hydrophobic bonding of these polypeptides leads to a progressive loss of PSD structure.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D009419	Nerve Tissue Proteins		Proteins, Nerve Tissue,Tissue Proteins, Nerve
D001921	Brain	The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.	Encephalon
D001923	Brain Chemistry	Changes in the amounts of various chemicals (neurotransmitters, receptors, enzymes, and other metabolites) specific to the area of the central nervous system contained within the head. These are monitored over time, during sensory stimulation, or under different disease states.	Chemistry, Brain,Brain Chemistries,Chemistries, Brain
D002458	Cell Fractionation	Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.	Cell Fractionations,Fractionation, Cell,Fractionations, Cell
D002499	Centrifugation, Density Gradient	Separation of particles according to density by employing a gradient of varying densities. At equilibrium each particle settles in the gradient at a point equal to its density. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Centrifugations, Density Gradient,Density Gradient Centrifugation,Density Gradient Centrifugations,Gradient Centrifugation, Density,Gradient Centrifugations, Density
D002918	Chymotrypsin	A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.	Alpha-Chymotrypsin Choay,Alphacutanée,Avazyme
D006018	Glycols	A generic grouping for dihydric alcohols with the hydroxy groups (-OH) located on different carbon atoms. They are viscous liquids with high boiling points for their molecular weights.
D000085	Acetates	Derivatives of ACETIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxymethane structure.	Acetate,Acetic Acid Esters,Acetic Acids,Acids, Acetic,Esters, Acetic Acid