ABSTRACT
OBJECTIVE: To investigate the role of cysteinyl leukotrienic (cysLT) antagonists on conjunctival nitric oxide (NO) release in experimental allergic conjunctivitis. METHODS: Zafirlukast, disodium cromoglycate or levocabastine were instilled into the C48/80-challenged eyes of male Wistar rats. The conjunctival histamine content and nitrite levels in the lavage fluid were quantified 45 min and 6 h post-challenge, respectively. Instillation of phosphate buffer saline reflected control treatment. Statistical analyses were performed by ANOVA. RESULTS: Topical challenge with C48/80 significantly altered the histamine and nitrite levels to 44.6 +/- 2.8% and 233 +/- 19% of the control (P < 0.01), respectively. Instillation of zafirlukast, disodium cromoglycate or levocabastine reversed the effect of C48/80 on nitrite release, its levels being 150 +/- 27%, 54 +/- 14% and 121 +/- 20% of the control (P > 0.05), respectively. Zafirlukast had no effect on the histamine content. CONCLUSIONS: By inhibiting the late-phase NO component of the conjunctival hypersensitivity response, cysLT antagonists might contribute to the management of ocular inflammatory responses.
