Localization of the glutamate transporter protein GLAST in rat retina.
Glutamate is a neurotransmitter in retina. Glutamate transporter proteins keep the resting extracellular glutamate concentration low. This is required for normal neurotransmission and prevents the extracellular concentration of glutamate from reaching toxic levels. Here we describe the light and electron microscopic localization of the glutamate transporter protein GLAST in rat retina using an antibody raised and affinity purified against a peptide corresponding to amino acid residues 522-541. The strongest immunocytochemical labelling was observed in the outer plexiform layer, ganglion cell layer, and optic disc. GLAST was found in Müller cell processes in all retinal layers, notably ensheathing the photoreceptor terminals in the outer plexiform layer, and in astrocytes close to vessels in the inner retina and optic disc. No labelling was observed in neurons. The electrophoretic mobility of GLAST in retina was similar to that in cerebellum. In conclusion, the findings are in agreement with those reported by Derouiche and Rauen [7], except that we did not detect any GLAST in the retinal pigment epithelium.
Lehre
K P
KP
Anatomical Institute, University of Oslo, Norway. k.p.lehre@basalmed.uio.no
Davanger
S
S
Danbolt
N C
NC
D000595:Amino Acid Sequence; D027322:Amino Acid Transport System X-AG; D000818:Animals; D000918:Antibody Specificity; D001253:Astrocytes / Q000737:chemistry; D001923:Brain Chemistry; D002352:Carrier Proteins / Q000032:analysis* / Q000276:immunology; D018698:Glutamic Acid / Q000493:pharmacokinetics; D006023:Glycoproteins / Q000032:analysis* / Q000276:immunology; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D010857:Pigment Epithelium of Eye / Q000737:chemistry / Q000166:cytology; D051381:Rats; D012160:Retina / Q000737:chemistry* / Q000166:cytology / Q000648:ultrastructure
D027322:Amino Acid Transport System X-AG; D002352:Carrier Proteins; D006023:Glycoproteins; D018698:Glutamic Acid