Standard Amblyopia Therapy in Adults with Longstanding Amblyopia Improves Visual Acuity and Contrast Sensitivity.

Purpose: Perceptual learning or dichoptic training may result in improved acuity in adult amblyopes. However, for amblyopic children (<18 years), most clinicians recommend standard part-time patching. The purpose of this study was to determine if standard amblyopia therapy results in an enhancement in vision in the amblyopic eye of adults.

Inhibitors of the Neutral Amino Acid Transporters ASCT1 and ASCT2 Are Effective in In Vivo Models of Schizophrenia and Visual Dysfunction.

The -methyl-d-aspartate receptor coagonist d-serine is a substrate for the neutral amino acid transporters ASCT1 and ASCT2, which may regulate its extracellular levels in the central nervous system (CNS). We tested inhibitors of ASCT1 and ASCT2 for their effects in rodent models of schizophrenia and visual dysfunction, which had previously been shown to be responsive to d-serine. L-4-fluorophenylglycine (L-4FPG), L-4-hydroxyPG (L-4OHPG), and L-4-chloroPG (L-4ClPG) all showed high plasma bioavailability when administered systemically to rats and mice.

Phenylglycine analogs are inhibitors of the neutral amino acid transporters ASCT1 and ASCT2 and enhance NMDA receptor-mediated LTP in rat visual cortex slices.

The N-methyl-d-aspartate receptor (NMDA) co-agonist d-serine is a substrate for the neutral amino acid transporters ASCT1 (SLC1A4) and ASCT2 (SLC1A5). We identified l-phenylglycine (PG) and its analogs as inhibitors of ASCT1 and ASCT2. PG analogs were shown to be non-substrate inhibitors of ASCT1 and ASCT2 with a range of activities relative to other amino acid transport systems, including sodium-dependent glutamate transporters, the sodium-independent d-serine transporter asc-1 and system L.

Restoration of visual performance by d-serine in models of inner and outer retinal dysfunction assessed using sweep VEP measurements in the conscious rat and rabbit.

The NMDA subtype of glutamate receptor and its co-agonist d-serine play a key role in synaptic function in the central nervous system (CNS), including visual cortex and retina. In retinal diseases such as glaucoma and macular degeneration, a loss of vision arises from malfunction of retinal cells, resulting in a glutamate hypofunctional state along the visual pathway in the affected parts of the visual field. An effective strategy to remedy this loss of function might be to increase extracellular levels of d-serine and thereby boost synaptic NMDA receptor-mediated visual transmission and/or plasticity to compensate for the impairment.

D-Serine Is a Substrate for Neutral Amino Acid Transporters ASCT1/SLC1A4 and ASCT2/SLC1A5, and Is Transported by Both Subtypes in Rat Hippocampal Astrocyte Cultures.

N-methyl-D-aspartate (NMDA) receptors play critical roles in synaptic transmission and plasticity. Activation of NMDA receptors by synaptically released L-glutamate also requires occupancy of co-agonist binding sites in the tetrameric receptor by either glycine or D-serine. Although D-serine appears to be the predominant co-agonist at synaptic NMDA receptors, the transport mechanisms involved in D-serine homeostasis in brain are poorly understood.