Modulation of NMDA receptor-mediated responses by glycine and D-serine in the rat thalamus in vivo.
The effects of iontophoretically applied glycine and D-serine upon responses of rat ventrobasal thalamus neurones to excitatory amino acids and sensory stimulation were investigated. Glycine inhibited excitatory responses to kainate, quisqualate and N-methyl-aspartate (NMA). Strychnine antagonised inhibitory responses to glycine, but in only a small number (2/7) of cases did such an antagonism reveal a facilitatory action of glycine on NMA responses. D-Serine inhibited responses of almost all neurones to either kainate or quisqualate, but enhanced responses to NMA on nearly half of the tested neurones, whilst having a weaker inhibitory action on the remainder. It is thus possible that D-serine has a dual action: (i) a facilitation of N-methyl-D-aspartate (NMDA) receptor-mediated responses and (ii) a non-selective inhibitory action.
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Department of Visual Science, Institute of Ophthalmology, London, U.K.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005998:Glycine / Q000494:pharmacology*; D007608:Kainic Acid / Q000494:pharmacology; D016202:N-Methylaspartate; D010069:Oxadiazoles / Q000494:pharmacology; D016318:Quisqualic Acid; D051381:Rats; D011919:Rats, Inbred Strains; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology*; D012694:Serine / Q000494:pharmacology*; D013331:Strychnine / Q000494:pharmacology; D013788:Thalamus / Q000187:drug effects / Q000502:physiology*
D010069:Oxadiazoles; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D001224:Aspartic Acid; D012694:Serine; D016202:N-Methylaspartate; D016318:Quisqualic Acid; D013331:Strychnine; D007608:Kainic Acid; D005998:Glycine