Light-evoked NMDA receptor-mediated currents are reduced by blocking D-serine synthesis in the salamander retina.
Experiments were carried out in the retina of the tiger salamander (Ambystoma tigrinum) to evaluate the importance of D-serine synthesis on light-evoked N-methyl D-aspartate (NMDA) receptor-mediated components of ganglion cells and contributions to the proximal negative field potential. We blocked the synthesis of D-serine through brief exposures of the retina to phenazine ethosulfate and validated the changes in the tissue levels of D-serine using capillary electrophoresis methods to separate and measure the amino acid enantiomers. Ten minute exposures to phenazine ethosulfate decreased D-serine levels in the retina by about 50% and significantly reduced the NMDA receptor contribution to light responses of the inner retina. This is the first report of a linkage between D-serine synthesis and NMDA receptor activity in the vertebrate retina.
Stevens
Eric R
ER
Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA.
Gustafson
Eric C
EC
Sullivan
Steven J
SJ
Esguerra
Manuel
M
Miller
Robert F
RF
D000557:Ambystoma / Q000502:physiology*; D000818:Animals; D019075:Electrophoresis, Capillary / Q000379:methods; D004594:Electrophysiology; D008027:Light; D018613:Microscopy, Confocal; D010619:Phenazines / Q000494:pharmacology; D010775:Photic Stimulation / Q000379:methods; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D012160:Retina / Q000166:cytology / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000502:physiology*; D012694:Serine / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000378:metabolism
D010619:Phenazines; D016194:Receptors, N-Methyl-D-Aspartate; C028122:5-ethylphenazine; D012694:Serine