title: Reaction of disodium cromoglycate with hydrated electrons.
abstract: A possible mechanism by which disodium cromoglycate (DSCG) prevents a decrease in regional cerebral blood flow but not hypotension in primates following whole body gamma-irradiation was studied. Several studies have implicated superoxide radicals (O2-.) in intestinal and cerebral vascular disorders following ischemia and ionizing radiation, respectively. O2-. is formed during radiolysis in the reaction between hydrated electrons (e-aq) and dissolved oxygen. For this reason, the efficiency of DSCG to scavenge e-q and possibly prevent the formation of O2-. was studied. Hydrated electrons were produced by photolysis of potassium ferrocyanide solutions. The rate constant, k = 2.92 x 10(10) M-1s-1 for the reaction between e-aq and DSCG was determined in competition experiments using the spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). This spin trap reacts rapidly with e-aq followed by protonation to yield the ESR observable DMPO-H spin adduct. The results show that DSCG is an efficient e-aq scavenger and may effectively compete with oxygen for e-aq preventing the radiolytic formation of O2-..
authors.affiliation: Radiation Sciences Department Armed Forces Radiobiology Research Institute, Bethesda, MD 20814-5145.
authors.forename: A J
authors.initials: AJ
authors.lastname: Carmichael
authors.forename: C M
authors.initials: CM
authors.lastname: Arroyo
authors.forename: L G
authors.initials: LG
authors.lastname: Cockerham
mesh_terms: D004205:Cromolyn Sodium; D003497:Cyclic N-Oxides; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D010782:Photolysis
chemical_list: D003497:Cyclic N-Oxides; C017245:5,5-dimethyl-1-pyrroline-1-oxide; D004205:Cromolyn Sodium