D-aspartate potentiates the effects of L-glutamate on horizontal cells in goldfish retina.
The amino acids L-glutamate and L-aspartate depolarize H1 horizontal cells in the perfused goldfish retina but only at millimolar concentrations. The effects of L-glutamate (but not of L-aspartate) are potentiated approximately 15-fold by exposure to D-aspartate. D-Aspartate blocks acidic amino acid uptake in goldfish retina, so that the potentiation of L-glutamate may be produced by an increase in its effective concentration at the horizontal cell membrane. Because D-aspartate also augments the light responses of horizontal cells, our results are consistent with the possibility that L-glutamate is a neurotransmitter of cone photoreceptors in goldfish.
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D006054:Goldfish; D008027:Light; D008564:Membrane Potentials / Q000187:drug effects; D012160:Retina / Q000166:cytology / Q000187:drug effects*; D013237:Stereoisomerism
D005971:Glutamates; D001224:Aspartic Acid; D018698:Glutamic Acid