Investigative ophthalmology & visual science
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Invest. Ophthalmol. Vis. Sci. · Mar 2006
Neuroglobin and cytoglobin: oxygen-binding proteins in retinal neurons.
The goal of this study was to describe the detailed localization of the novel oxygen-binding molecules, neuroglobin (Ngb) and cytoglobin (Cygb), in mammalian retinas and to determine whether Ngb and Cygb are neuronal or glial proteins in the retina. ⋯ Ngb and Cygb are widely distributed in retinal neurons and RPE, but not in glial cells of the canine retina. Their structure and distribution is suggestive of a possible role in oxygen transport in the mammalian retina.
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Invest. Ophthalmol. Vis. Sci. · Mar 2006
Randomized Controlled TrialIntravenous administration of diphenhydramine reduces histamine-induced vasodilator effects in the retina and choroid.
Intravenous administration of histamine causes an increase in choroidal blood flow (ChBF) and retinal vessel diameters in healthy subjects. The receptor mediating this response has not yet been identified. The present study was undertaken to clarify whether H1 receptor blockade with diphenhydramine affects the hemodynamic response of histamine in the choroid and the retina. ⋯ The present data confirm that histamine increases ChBF and retinal vessel diameters in healthy subjects. Administration of the H1 receptor blocker diphenhydramine significantly reduced histamine-induced changes in ocular perfusion parameters. These results strongly indicate that in the retina and choroid, H1 receptors are involved in the histamine-mediated hemodynamic effects in vivo.
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Invest. Ophthalmol. Vis. Sci. · Dec 2005
Randomized Controlled TrialSystemic omega-6 essential fatty acid treatment and pge1 tear content in Sjögren's syndrome patients.
To determine the effect of oral omega-6 essential fatty acids on PGE(1) tear content and signs and symptoms of ocular discomfort in patients with Sjögren's syndrome (SS). ⋯ Omega-6 administration increases the PGE1 levels in tears of patients with SS and improves ocular surface signs and symptoms of ocular discomfort.
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Invest. Ophthalmol. Vis. Sci. · Nov 2005
Parasympathetic mediated pupillary dilation elicited by lingual nerve stimulation in cats.
To determine the autonomic efferent nerve pathways for the reflex pupillary dilation elicited by somatic stimulation in cats. ⋯ These results indicate that the Vsp and EW nucleus act as bulbar relay centers for pupillary dilation elicited by LN stimulation and suggest that the efferent arc of the response is a parasympathetic pathway. The contralateral pupillary dilation appears to be mediated, at least in part, by fibers projecting from the Vsp to the contralateral EW nucleus.
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Invest. Ophthalmol. Vis. Sci. · Oct 2005
A developmental switch in the expression of aquaporin-4 and Kir4.1 from horizontal to Müller cells in mouse retina.
In adult retina, aquaporin-4 (AQP4) and inwardly rectifying K(+) (Kir4.1) channels localize to astrocyte and Müller cell membranes facing vascular and vitreous compartments, optimizing clearance of extracellular K(+) and water from the synaptic layers. However, it is unknown whether these channels are expressed at early developmental stages, before gliogenesis or angiogenesis take place in the neural retina. This study was conducted to determine the presence of AQP4 and Kir4.1 proteins in the developing mouse retina. ⋯ The findings showed that AQP4 and Kir4.1 protein expression is confined to differentiating horizontal cells before its expression in Müller cells. The finding of AQP4 in neurons is novel, since AQP4 expression within the central nervous system is restricted to glia. Also, the results demonstrated that AQP4 is a horizontal cell-specific immunomarker in neonatal retina. The transitory coexpression of AQP4 and Kir4.1 proteins by differentiating horizontal interneurons suggests that these cells mediate K(+) and water transcellular uptake until the initiation of phototransduction, when glial cells assume these functions.