+ Most Popular
Cunninghamia lanceolata plantations in China
Mammalian lairs in paleo ecological studies and palynology
Studies on technological possibilities in utilization of anhydrous milk fat for production of recombined butter-like products
Should right-sided fibroelastomas be operated upon?
Large esophageal lipoma
Apoptosis in the mammalian thymus during normal histogenesis and under various in vitro and in vivo experimental conditions
Poissons characoides nouveaux ou non signales de l'Ilha do Bananal, Bresil
Desensitizing efficacy of Colgate Sensitive Maximum Strength and Fresh Mint Sensodyne dentifrices
Administration of fluid by subcutaneous infusion: revival of a forgotten method
Tundra mosquito control - an impossible dream?
Schizophrenia for primary care providers: how to contribute to the care of a vulnerable patient population
Geochemical pattern analysis; method of describing the Southeastern limestone regional aquifer system
Incidence of low birth weights in a hospital of Mexico City
Graded management intensity of grassland systems for enhancing floristic diversity
Microbiology and biochemistry of cheese and fermented milk
The ember tetra: a new pygmy characid tetra from the Rio das Mortes, Brazil, Hyphessobrycon amandae sp. n. (Pisces, Characoidei)
Risk factors of contrast-induced nephropathy in patients after coronary artery intervention
Renovation of onsite domestic wastewater in a poorly drained soil
Observations of the propagation velocity and formation mechanism of burst fractures caused by gunshot
Systolic blood pressure in a population of infants in the first year of life: the Brompton study
Haematological studies in rats fed with metanil yellow
Studies on pasteurellosis. I. A new species of Pasteurella encountered in chronic fowl cholera
Dormancy breaking and germination of Acacia salicina Lindl. seeds
therapy of lupus nephritis. a two-year prospective study

Hydroxyl free-radical spin-adduct in rat brain synaptosomes. Observations on the reduction of the nitroxide

Hydroxyl free-radical spin-adduct in rat brain synaptosomes. Observations on the reduction of the nitroxide

Biochimica et Biophysica Acta 756(2): 204-216

ISSN/ISBN: 0006-3002

PMID: 6299374

DOI: 10.1016/0304-4165(83)90093-4

Understanding the prevalence and action of hydroxyl free-radicals, damaging species in biological systems, is improved by spin-trapping techniques. The hydroxyl free-radical rapidly adds to the spin-trap 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) to form a relatively stable nitroxyl free-radical spin-adduct (DMPO-OH), but it was found that DMPO-OH becomes diamagnetic, presumably by chemical reduction, when it is added to rat brain synaptosomes. DMPO-OH reduction by synaptosomes was a time-dependent process, starting immediately and continuing up to 20 min or more, when almost all the spin-adduct is reduced. During synaptosomal reduction, the electron paramagnetic resonance (EPR) high field line of DMPO-OH is broadened indicating restrictions on the motion of the nitroxide. This was not due to simple absorption of DMPO-OH to proteins. Experiments with the spin-adduct in glycerol at low temperatures showed that DMPO-OH experienced, during synaptosomal reduction, restricted motion having a correlation time of about 3.3 X 10(-9)s. This value would be expected if DMPO-OH was near the polar region of the hydrocarbon layer of a membrane bilayer. Synaptosomal membrane transport of DMPO-OH was tested by competition studies, since it was presumed that this nitroxide was transported and then reduced inside the synaptosomes. Several compounds tested, including amino acids, neurotransmitters, food dyes, and many others, that may have acted competitively in transport were not effective in slowing down reduction of DMPO-OH. However, it was found that azide, cyanide and heating of the synaptosomes markedly decreased the rate of synaptosomal reduction of DMPO-OH. Azide at 50 microM manifested one-half of its maximal inhibitory effect. Experiments with 1-octanol to obtain a measure of the membrane partition of DMPO-OH demonstrated that the octanol/water distribution was 1.83. Experiments with glass microfibre filtration to determine synaptosomal binding revealed that DMPO, as well as apparently DMPO-OH, were not specifically retained by synaptosomes. All of these results combined with past work on nitroxide reduction by biological systems, suggest that DMPO-OH reduction by synaptosomes is due to its interaction with and reduction by electron transport carriers of mitochondria within the synaptosomes.

Please choose payment method:

(PDF emailed within 0-6 h: $19.90)

Accession: 043297136

Download citation: RISBibTeXText

Related references

Optimal EPR detection of weak nitroxide spin adduct and ascorbyl free radical signals. Journal of Biochemical and Biophysical Methods 24(1-2): 147-151, 1992

Effect of plant phenolics on the formation of the spin-adduct of hydroxyl radical and the DNA strand breaking by hydroxyl radical. Biological and Pharmaceutical Bulletin 19(4): 558-563, 1996

Hydroxyl radical production by free and DNA-bound aminoquinone antibiotics and its role in DNA degradation. Electron spin resonance detection of hydroxyl radicals by spin trapping. Canadian Journal of Biochemistry 56(11): 1042-1047, 1978

Spin trapping evidence for the lack of significant hydroxyl radical production during the respiration burst of human phagocytes using a spin adduct resistant to superoxide-mediated destruction. Journal of Biological Chemistry 265(5): 2650-2656, 1990

Rapid reduction of ATP synthesis and lack of free radical formation by MPP+ in rat brain synaptosomes and mitochondria. Brain Research 975(1-2): 214-221, 2003

A quantum-chemical study for spin adduct of phenyl tert-butyl nitrone and 2-hydroxyl 3-hexene 5-ol radical. Journal of Molecular Structure 604(2-3): 245-251, 2002

Melatonin prevents the increase in hydroxyl radical-spin trap adduct formation caused by the addition of cisplatin in vitro. Life Sciences 72(15): 1773-1780, 2003

Hydroxyl free radical adduct of deoxyguanosine: sensitive detection and mechanisms of formation. Free Radical Research Communications 1(3): 163-172, 1986

Spin traps inhibit formation of hydrogen peroxide via the dismutation of superoxide: implications for spin trapping the hydroxyl free radical. Biochimica et Biophysica Acta 1075(3): 213-222, 1991

Hydroxyl free radical reactions with amino acids and proteins studied by electron spin resonance spectroscopy and spin-trapping. Biochimica et Biophysica Acta 790(3): 238-250, 1984

Kinetic Study and Theoretical Analysis of Hydroxyl Radical Trapping and Spin Adduct Decay of Alkoxycarbonyl and Dialkoxyphosphoryl Nitrones in Aqueous Media. Journal of Physical Chemistry A 107(22): 4407-4414, 2003

The antioxidative effect of a novel free radical scavenger 4'-hydroxyl-2-substituted phenylnitronyl nitroxide in acute high-altitude hypoxia mice. Biological and Pharmaceutical Bulletin 36(6): 917-924, 2013

Spin-quenching by oxygen of a radiosensitizing nitroxide free radical in aqueous solution. International Journal of Radiation Biology and Related Studies in Physics Chemistry and Medicine 17(6): 591-593, 1970

Formation of 8-hydroxydeoxyguanosine, hydroxyl free radical adduct of DNA in granulocytes exposed to the tumor promoter, tetradecanoylphorbolacetate. Biochemical and Biophysical Research Communications 137(2): 841-846, 1986

Free radical reactions induced by hydroxyl radical attack on cytosine related compounds a study by a method combining esr spin trapping and hplc. Nucleic Acids Research 18(5): 1217-1224, 1990