Coincidence of L‐glutamate/L‐aspartate transporter (GLAST) and glutamine synthetase (GS) immunoreactions in retinal glia: Evidence for coupling of GLAST and GS in transmitter clearance

Journal of Neuroscience Research - Tập 42 Số 1 - Trang 131-143 - 1995
Amin Derouiche1,2, Thomas Rauen1
1Department of Neuroanatomy, Max-Planck Institute for Brain Research, Frankfurt/M., Germany
2Institute of Anatomy, J.W. Goethe University, Frankfurt/M., Germany

Tóm tắt

AbstractOur aim was to identify proteins that mediate the uptake and degradation of synaptically released glutamate, focusing on the rat retina with its well‐defined glutamatergic pathways. Immunoreactivity against the L‐glutamate/L‐aspartate transporter (GLAST) is present in Müller cells. Ultrastructurally, even the finest glial processes, particularly those ensheathing identified structures of glutamatergic transmission (rod spherules), are immunoreactive for GLAST. Further light and electron microscopic observations revealed that also retinal astrocytes and pigment epithelial cells are immunoreactive for GLAST. No neuronal or microglial staining was observed. This is in line with uptake of exogenous [3H]glutamate previously localized specifically in Müller cells and pigment epithelium (Ehinger and Falck: Brain Res 33:157‐172, 1971). Since endogenous glutamate can only be demonstrated in Muller cells if glutamine synthetase (GS) is inhibited (Pow and Robinson: Neuroscience 60:355‐366, 1994), the immunocytochemical localization of GS was determined. GS immunoreactivity was found in all but only those cell types immunoreactive for GLAST. The light and electron microscopic patterns of immunoreactivity were very similar, particularly in the outer plexiform layer: The three cell types containing both GS and GLAST (Müller cells, astrocytes, and retinal pigment epithelium) are related developmentally. In the light of the two references quoted the present data indicate that the proteins mediating retinal uptake and degradation of synaptically released glutamate may be GLAST and GS, respectively, and that they may operate in concert to terminate the neurotransmitter action of glutamate. © 1995 Wiley‐Liss, Inc.

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Tài liệu tham khảo

10.1016/0896-6273(93)90145-H

10.1113/jphysiol.1993.sp019735

10.1111/j.1471-4159.1979.tb11705.x

10.1016/0301-0082(94)90033-7

10.1016/0306-4522(92)90316-T

10.1016/0006-8993(91)90103-3

10.1111/j.1460-9568.1993.tb00477.x

10.1016/0006-8993(71)90314-3

10.1007/BF01175194

Fedoroff S, 1986, Astrocytes. Development, Morphology, and Regional Specialization of Astrocytes, 35

10.1007/BF00492479

10.1007/BF00271288

10.1016/0006-8993(84)90810-2

Hertz L, 1986, Astrocytes. Biochemistry, Physiology, and Pharmacology of Astrocytes, 179

10.1002/cne.903130405

10.1038/360467a0

Klöckner U, 1993, Electrogenic L‐glutamate uptake in Xenopus laevis oocytes expressing a cloned rat brain L‐glutamate/L‐aspartate transporter (GLAST1), J Biol Chem, 268, 14594, 10.1016/S0021-9258(18)82373-0

10.1016/0306-4522(86)90112-0

10.1016/S0074-7696(08)60771-8

10.1016/0014-4835(88)90067-X

10.1111/j.1749-6632.1984.tb12369.x

10.1016/0165-3806(84)90077-4

10.1016/0006-8993(72)90540-9

10.1126/science.14400

Massey SC, 1990, Progress in Retinal Research, 399

10.1016/0301-0082(87)90005-0

Neal MJ, 1971, Uptake of 14C‐L‐glutamate by rat retina, Br J Pharmacol, 43, 442

10.1177/27.3.39099

10.1016/0006-8993(79)90071-4

Peters A, 1976, The Fine Structure of the Nervous System: The Neurons and Supporting Cells

10.1016/0014-5793(84)80563-3

10.1016/0306-4522(94)90249-6

10.1016/0304-3940(94)90375-1

10.1016/0014-5793(92)81401-7

ReicheltWStabelJPannickeTHeinemannU(1994): Glutathione synthesis is limited by the velocity of the Na+ /glutamate transporter in Muller glial cells. Society for Neuroscience Meeting Miami Abstract No. 267.11.

10.1038/268654a0

10.1016/0014-4835(78)90022-2

10.1016/0896-6273(94)90038-8

10.1002/glia.440110103

10.1073/pnas.89.22.10955

10.1111/j.1460-9568.1994.tb00587.x

Towebin H, 1979, Electrophoretic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: Procedure and some applications, Proc Natl Acad Sci USA, 76, 4350, 10.1073/pnas.76.9.4350

10.1152/physrev.1991.71.2.447

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Journal of Neuroscience Research

Tập 42 Số 1

131-143

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