Role of catalase in pre- and postjunctional responses of mammalian irides to hydrogen peroxide

Beverly Matutte, S. Olubusayo Awe, Ferdy A. Ameh, Angela M. Leday, Justin C. Rice, Catherine A. Opere, Sunny E. Ohia

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5 Scopus citations

Abstract

In the present study, we examined the effect of inhibition of catalase with 3-amino-triazole (3-AT) on hydrogen peroxide (H2O2)-induced enhancement of sympathetic neuro-transmission in bovine irides and on the inhibitory effect of this oxidant on norepinephrine (NE) release from human irides, in vitro. Furthermore, we investigated the effect of 3-AT on H2O2-induced attenuation of contractile responses to carbachol in the bovine isolated irides. Isolated mammalian irides were prepared for studies of [3H]NE release using the superfusion method and for contractile studies using isolated organ baths. At concentrations less than 100 μM, H2O2 had no significant effect on field-stimulated [3H]NE release from bovine or human irides. In bovine irides, 3-AT caused significant (P <0.001) leftward shifts of concentration-response curves to H2O2 (10 - 300 μM). 3-AT also increased H2O2-induced attenuation of evoked [3H]NE release from human isolated irides. Low concentrations of H2O2 (<100 μM) had no effect on carbachol contractions. However, 3-AT unmasked an inhibitory effect of low concentrations of H2O2 (3 - 100 μM) on carbachol-induced contractions. We conclude that inhibition of catalase causes both pre- and postjunctional responses of isolated mammalian irides to be more susceptible to oxidative stress induced by H2O2.

Original languageEnglish (US)
Pages (from-to)429-438
Number of pages10
JournalJournal of Ocular Pharmacology and Therapeutics
Volume16
Issue number5
DOIs
StatePublished - Jan 1 2000

All Science Journal Classification (ASJC) codes

  • Ophthalmology
  • Pharmacology
  • Pharmacology (medical)

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