title: Effect of peroxides on [3H]D-aspartate release from bovine isolated retinae.
abstract: In the present study, we investigated the effect of naturally occurring and synthetic peroxides on K+-depolarization-evoked release of [3H]D-aspartate from bovine isolated retinae. Furthermore, effect of peroxides on endogenous glutamate concentrations were measured by HPLC in bovine neural retinae and vitreous humor of eyes treated with hydrogen peroxide (H2O2) ex vivo. Both naturally occurring H2O2 (1-100 microM) and synthetic (cumene hydroperoxide, cuOOH; 1-100 microM) peroxides caused a concentration-dependent inhibition of K+-evoked [3H]D-aspartate release without affecting basal tritium efflux. The antioxidant, trolox (2 mM) prevented the inhibition of evoked [3H]D-aspartate overflow elicited by both H2O2 (30 microM) and cuOOH (10 microM). Inhibition of catalase by 3-amino-triazole (3- AT 100 mM) enhanced an inhibitory effect of a low concentration of H2O2 (1 microM) but antagonized the effect of H2O2 (30 microM) on K+-induced [3H]D-aspartate release. In ex vivo experiments, exogenously applied H2O2 (1-100 microM) also caused a concentration-related decrease in glutamate levels in the bovine retina. We conclude that peroxides can inhibit K+-evoked release of [3H]D-aspartate and also decrease endogenous glutamate concentrations in the bovine retina.
authors.affiliation: Department of Pharmacy Sciences, School of Pharmacy and Health Professions, Creighton University Medical Center, Omaha, Nebraska, USA.
authors.forename: Angela M
authors.initials: AM
authors.lastname: LeDay
authors.forename: Sunday O
authors.initials: SO
authors.lastname: Awe
authors.forename: Kaustubh
authors.initials: K
authors.lastname: Kulkarni
authors.forename: Lydia C
authors.initials: LC
authors.lastname: Harris
authors.forename: Catherine
authors.initials: C
authors.lastname: Opere
authors.forename: Alekha
authors.initials: A
authors.lastname: Dash
authors.forename: Sunny E
authors.initials: SE
authors.lastname: Ohia
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism*; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D009924:Organ Culture Techniques; D010545:Peroxides / Q000494:pharmacology*; D012160:Retina / Q000187:drug effects* / Q000378:metabolism; D014316:Tritium
chemical_list: D010545:Peroxides; D014316:Tritium; D001224:Aspartic Acid