Elevated glucose alters the content and distribution of
AMPA receptor subunits in retinal neural cellS
-
1
University of Coimbra, Center of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, Portugal
-
2
University of Coimbra, Center for Neuroscience and Cell Biology, Department of Zoology, Portugal
Diabetic retinopathy is a leading cause of visual impairment and blindness among adults in western countries. Although it is considered a microvascular disease, diabetic patients present impairments in contrast sensitivity and color vision, even before the detection of alterations in blood-retinal barrier, indicating that neural retina is also affected by diabetes. Moreover, some studies have suggested that alterations in glutamatergic transmission may be involved in retinal dysfunction and neurodegeneration during diabetes. The aim of this work was to investigate whether elevated glucose or diabetes affect the total content or surface levels of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR) subunits. Rat retinal neural cells were isolated from newborn Wistar rats and were cultured for 7 days. Retinal neural cells were exposed to elevated concentrations of D-glucose (30 mM) or D-mannitol (24.5 mM + 5.5 mM glucose), which was used as an osmotic control, for several time periods (24, 48 or 96 h). Type 1 diabetes was induced in Wistar rats (2, 4 or 8 weeks duration) by an intraperitoneal injection of streptozotocin. The surface levels of GluR1, GluR2 and GluR4 were evaluated by a biotinylation assay and the immunoreactivity of total levels of these subunits was assessed by western blotting and immunocytochemistry.
Elevated glucose, but not mannitol, significantly increased the total content of GluR2 subunit for all time points studied in retinal neural cells. Total protein levels of GluR1 and GluR4 subunits were not affected by elevated glucose. However, the exposure to elevated glucose, but not mannitol, increased the surface levels of GluR1, GluR2 and GluR4 subunits. In whole retinas, the total content of GluR1, GluR2 and GluR4 was not altered by diabetes (2, 4 or 8 weeks). In summary, these results show that elevated glucose changes the levels and/or distribution of AMPAR subunits in rat retinal neural cells, which may contribute to visual impairments associated with diabetic retinopathy. Although we did not find significant changes in the total content of AMPA receptor subunits in diabetic retinas, we cannot exclude possible changes in the composition and distribution of AMPA receptors in particular retinal cells or retinal layers.
Support: FCT (Project PTDC/SAU-NEU/71228/2006)
Conference:
11th Meeting of the Portuguese Society for Neuroscience, Braga, Portugal, 4 Jun - 6 Jun, 2009.
Presentation Type:
Poster Presentation
Topic:
Neuronal Communication
Citation:
Castilho
A,
Liberal
JM,
Gaspar
JM,
Baptista
F,
Carvalho
AL and
Ambrosio
AF
(2009). Elevated glucose alters the content and distribution of
AMPA receptor subunits in retinal neural cellS.
Front. Neurosci.
Conference Abstract:
11th Meeting of the Portuguese Society for Neuroscience.
doi: 10.3389/conf.neuro.01.2009.11.144
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
11 Aug 2009;
Published Online:
11 Aug 2009.
*
Correspondence:
Aurea Castilho, University of Coimbra, Center of Ophthalmology and Vision Sciences, IBILI, Faculty of Medicine, Alicante, Portugal, aureacastilho@netcabo.pt