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Topical Naltrexone Restores Normal Tear Production in Rats
Author(s) -
Zagon Ian S.,
Campbell Anna M.,
Sassani Joseph W.,
McLaughlin Patricia J.
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1071.3
Subject(s) - naltrexone , medicine , opioid antagonist , eye drop , antagonist , ophthalmology , dry eyes , eye disease , tears , endocrinology , anesthesia , receptor , (+) naloxone , surgery
Dry eye is a common ophthalmological condition, with an estimated prevalence of 5% to 30% depending on age. It represents a complex, multifactorial disease. Dry eye in diabetic rats can be reversed with topical application of the opioid antagonist naltrexone (NTX). We have discovered that normal rats have transient periods of dry eye that can be detected for 3 to 6 days. The present study examined the hypothesis that topical application of NTX restores tear production in normal, healthy rats with spontaneous episodic dry eye. Adult male rats with Schirmer test scores of 6.5 or less were defined as having dry eye and were treated with a single eye drop of 10‐5 M NTX or sterile vehicle. Rats with normal tear production were also treated with NTX. Episodic dry eye was reversed by one drop of NTX within 1 hour of administration, with reversal lasting at least 48 hours. NTX had no effect on rats with normal tear production. No changes in corneal sensitivity were noted in any group of rats. Dry eye does occur in normal rats, appears to be due to an exaggerated opioid‐receptor interaction, and can be reversed by topical treatment with NTX. Thus, NTX is a non‐toxic, rapidly acting, and highly effective agent, with one drop lasting for days. The data represent a paradigm shift in clinical practice for understanding the pathogenesis and treatment of dry eye.