title: Diabetes causes transient changes in the composition and phosphorylation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors and interaction with auxiliary proteins in the rat retina.
abstract: OBJECTIVE
  The impairment of glutamatergic neurotransmission has been associated with diabetic complications in the central nervous system, such as diabetic retinopathy. Here, we investigated the effect of elevated glucose exposure and diabetes on α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor composition, subunit phosphorylation, and the association of the GluA2 subunit with accessory proteins in the retina.
  
  
  METHODS
  The subunit composition of AMPA receptors and the association of the GluA2 subunit with modulatory proteins were evaluated with coimmunoprecipitation in retinal neural cell cultures and in the retina of experimentally induced-diabetic rats. The phosphorylation status of AMPA receptor subunits was evaluated with western blotting.
  
  
  RESULTS
  In retinal neural cell cultures, elevated glucose did not significantly alter the composition of AMPA receptors, namely, the interactions between the GluA1, GluA2, and GluA4 subunits, but reduced GluA2 association with GRIP1. Moreover, elevated glucose did not cause changes on the level of GluA1 phosphorylated at serine residues 831 and 845. Diabetes induced early transitory changes in the interaction between AMPA receptor subunits GluA1, GluA2, and GluA4. At 8 weeks of diabetes, the content of GluA1 phosphorylated at serine 831 or serine 845 in the retina increased, compared to age-matched controls.
  
  
  CONCLUSIONS
  Taken together, these results suggest that diabetes induces dynamic changes in AMPA receptor subunit composition, which could affect glutamatergic transmission in the rat retina.
authors: Centre of Ophthalmology and Vision Sciences, Institute for Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal.
authors: Aurea F
authors: AF
authors: Castilho
authors: Centre of Ophthalmology and Vision Sciences, Institute for Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal.
authors: Joana T
authors: JT
authors: Liberal
authors: Centre of Ophthalmology and Vision Sciences, Institute for Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal.
authors: Filipa I
authors: FI
authors: Baptista
authors: Centre of Ophthalmology and Vision Sciences, Institute for Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal ; Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.
authors: Joana M
authors: JM
authors: Gaspar
authors: Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal ; Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
authors: Ana Luísa
authors: AL
authors: Carvalho
authors: Centre of Ophthalmology and Vision Sciences, Institute for Biomedical Imaging and Life Sciences (IBILI), University of Coimbra, Coimbra, Portugal ; Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal ; AIBILI, Coimbra, Portugal.
authors: António F
authors: AF
authors: Ambrósio
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003920:Diabetes Mellitus / Q000378:metabolism* / Q000473:pathology; D005136:Eye Proteins / Q000378:metabolism*; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism; D011485:Protein Binding; D021122:Protein Subunits / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000378:metabolism*; D012160:Retina / Q000378:metabolism* / Q000473:pathology; D055351:Retinal Neurons / Q000378:metabolism / Q000473:pathology
chemical_list: D001786:Blood Glucose; D005136:Eye Proteins; D021122:Protein Subunits; D018091:Receptors, AMPA; D010768:Phosphoserine