DAY AND NIGHT DYSFUNCTION IN INTRARETINAL MELATONIN AND RELATED INDOLEAMINES METABOLISM, CORRELATED WITH THE DEVELOPMENT OF GLAUCOMA-LIKE DISORDER IN AN AVIAN MODEL

As previous studies have suggested that melatonin and serotonin may be involved in the regulation of intraocular pressure, retinal concentra tions of melatonin, 5-HT, and related indoleamines measured at day and at night were studied during the development of a glaucoma-like disor der with increased intraocular pressure in the al mutant quail. Indole amine levels were determined by HPLC with electrochemical detection in 1-month-, 3-month-, and 7-month-old al mutant and control quails. Mor phology and numbers of melatonin-synthesizing and 5-HT-containing cell s, labelled immunohistochemically with an anti-hydroxyindol-0-methyltr ansferase (HIOMT) antibody and an anti-5-HT antibody, respectively, we re studied. Major findings were that: (1) no significant changes in mo rphology of melatonin-synthesizing cells or in the morphology and dens ity of 5-HT-containing amacrine cells were observed during the d velop ment of glaucoma: (2) 5-HT metabolism was modified during the night at 1 month of age and during the day after 3 months; and (3) melatonin m etabolism was modified during the night at 7 months and during the day after 3 months. These results demonstrate a relationship between the temporal evolution of this avian glaucoma and a dysfunction in indolea mine retinal metabolism.