Local differences in GABA release induced by excitatory amino acids during retina development: selective activation of NMDA receptors by aspartate in the inner retina.
Glutamate and GABA are the major excitatory and inhibitory neurotransmitters in the CNS. In the retina, it has been shown that glutamate and aspartate and their agonists kainate and NMDA promote the release of GABA. In the chick retina, at embryonic day 14 (E14), glutamate and kainate were able to induce the release of GABA from amacrine and horizontal cells as detected by GABA-immunoreactivity. NMDA also induced GABA release restricted to amacrine cell population and its projections to the inner plexiform layer (E14 and E18). Although aspartate reduced GABA immunoreactivity, specifically in amacrine cells of E18 retinas, it was not efficient to promote GABA release from retinas at E14. As observed in differentiated retinas, dopamine inhibited the GABA release promoted by NMDA and aspartate but not by kainate. Our data show that different retinal sites respond to distinct EAAs via different receptor systems.
Departamento de Neurobiologia do Instituto de Biologia, Universidade Federal Fluminense, Niterói, RJ, Brasil.
Karin da Costa
Kda C
Calaza
Maria Christina Fialho
MC
de Mello
Fernando Garcia
FG
de Mello
Patrícia Franca
PF
Gardino
D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism; D002642:Chick Embryo; D018846:Excitatory Amino Acids / Q000378:metabolism* / Q000494:pharmacology; D050485:GABA Plasma Membrane Transport Proteins; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007608:Kainic Acid / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D016202:N-Methylaspartate / Q000494:pharmacology; D027361:Organic Anion Transporters; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists / Q000378:metabolism*; D012160:Retina / Q000187:drug effects / Q000196:embryology / Q000378:metabolism*; D015053:Zygote; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D002352:Carrier Proteins; D018846:Excitatory Amino Acids; D050485:GABA Plasma Membrane Transport Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D027361:Organic Anion Transporters; D016194:Receptors, N-Methyl-D-Aspartate; D001224:Aspartic Acid; D005680:gamma-Aminobutyric Acid; D016202:N-Methylaspartate; D007608:Kainic Acid