Biomaterial Database

A spin label study of rat brain membranes. Effects of temperature and divalent cations. 1976

J Viret, and F Leterrier

Rat brain myelin, synaptosomal plasma membranes and synaptic vesicles were spin labelled with stearic acid nitroxide derivatives. Their electron spin resonance spectra were studied as a function of temperature and devalent ions (Ca2+ and Mg2+) concentrations. (1) Synaptosomal plasma membranes and synaptic vesicles show identical temperature variations of their order parameter (S = 0.58 at 35 degrees C and S = 0.72 AT 22 DEGREES C). Myelin appears more rigid (S = 0.66 at 35 degrees C and S = 0.76 at 22 degrees C). A discontinuity of the order parameter variation as a function of temperature, is observed between 14.5 degrees C and l9.5 degrees C with the three types of membranes. (2) The hydrophobic core of these membranes is very fluid. No transition temperature is observed. The measured values of the spin label rotation correlation times and rotational activation energies are 2.1 and 2.8 ns at 35 degrees C and 3.1 and 3.6 kcal/mol respectively for synaptosomal plasma membranes and myelin. (3) Ca2+ enhances the membrane rigidity (12+/-0.7% increase of the order parameter at 35 degrees C in the presence of 10(-3) M Ca2+) and increases the transition temperature. At a lower extend, similar effects are observed with Mg2+.

UI	MeSH Term	Description	Entries
D008274	Magnesium	A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
D008566	Membranes	Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures.	Membrane Tissue,Membrane,Membrane Tissues,Tissue, Membrane,Tissues, Membrane
D009186	Myelin Sheath	The lipid-rich sheath surrounding AXONS in both the CENTRAL NERVOUS SYSTEMS and PERIPHERAL NERVOUS SYSTEM. The myelin sheath is an electrical insulator and allows faster and more energetically efficient conduction of impulses. The sheath is formed by the cell membranes of glial cells (SCHWANN CELLS in the peripheral and OLIGODENDROGLIA in the central nervous system). Deterioration of the sheath in DEMYELINATING DISEASES is a serious clinical problem.	Myelin,Myelin Sheaths,Sheath, Myelin,Sheaths, Myelin
D009928	Organ Specificity	Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.	Tissue Specificity,Organ Specificities,Specificities, Organ,Specificities, Tissue,Specificity, Organ,Specificity, Tissue,Tissue Specificities
D011189	Potassium Chloride	A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.	Slow-K,Chloride, Potassium
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
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004578	Electron Spin Resonance Spectroscopy	A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.	ENDOR,Electron Nuclear Double Resonance,Electron Paramagnetic Resonance,Paramagnetic Resonance,Electron Spin Resonance,Paramagnetic Resonance, Electron,Resonance, Electron Paramagnetic,Resonance, Electron Spin,Resonance, Paramagnetic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012965	Sodium Chloride	A ubiquitous sodium salt that is commonly used to season food.	Sodium Chloride, (22)Na,Sodium Chloride, (24)NaCl