Purchase this article with an account.
Krista Beach, Baskar Arumugam, Li-Fang Hung, Earl L Smith, Lisa A Ostrin; Adenosine Receptor Immunoreactivity in the Non-Human Primate Ocular Posterior Segment. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5463.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Adenosine receptor (ADOR) antagonists such as 7-methylxanthine (7-mx) have been shown to slow myopia progression. Adenosine receptors are found throughout the body, and regulate the release of neurotransmitters such as dopamine and glutamate. However, the role of adenosine in eye growth is unclear. Evidence suggests that 7-mx increases scleral collagen fibril diameter, hence, stiffening the sclera and preventing axial elongation. This study used immunohistochemistry (IHC) to examine the distribution of the ADORs in the posterior segment of the normal monkey eye to help elucidate the mechanism of action.
Eyes were enucleated from two male Rhesus monkeys (age 150 days). Anterior segments were removed, and eyecups were fixed in 4% paraformaldehyde (PFA), cryoprotected with successive sucrose infiltrations, dissected into leaflets, and flash-frozen. Tissue was cryosectioned, post-fixed with 4% PFA, washed with water and Hank’s Balanced Salt Solution (HBSS), blocked, and incubated overnight with primary antibody (ADORA1 1:100; ADORA2a 1:100; ADORA2b 1:50; and ADORA3 1:100). Sections were washed with HBSS, and secondary antibody (AlexaFluor488 goat anti-rabbit) was applied for 1 hour. Sections were washed, coverslipped with Prolong Diamond with DAPI (Molecular Probes), and imaged.
All four anti-ADORA antibodies showed high immunoreactivity in somas in the ganglion cell layer, and moderate immunoreactivity in photoreceptor inner segments. A1 staining was conspicuous in the outer plexiform layer and in the retinal nerve fiber layer (RNFL), but mostly absent in the RPE, choroid and sclera. A2a staining was high in the RNFL and outer choroid, moderate in scleral fibroblasts and throughout the retina, and mostly absent in the RPE. A2b staining was high in isolated scleral fibroblasts and occasional nuclei in the RPE, moderate in the outer and inner plexiform layers and the RNFL, and mostly absent in the choroid. A3 staining was conspicuous in photoreceptor processes spanning the outer nuclear layer, and was moderate in the RNFL, the choroid, and in scleral fibroblasts.
IHC indicated differential patterns of expression of the four adenosine receptors in the retina, choroid, and sclera of the normal non-human primate eye. The presence of ADORs in scleral fibroblasts suggests a mechanism by which ADOR antagonists may increase scleral stiffness to prevent myopia.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
This PDF is available to Subscribers Only