Quinolinate differentiates between forebrain and cerebellar NMDA receptors.
The potency of N-methyl-D-aspartate (NMDA), ibotenate, L-glutamate and quinolinate for inhibiting [3H]L-glutamate binding to rat brain NMDA receptors was determined by quantitative autoradiography. In contrast to NMDA, ibotenate and L-glutamate, quinolinate more potently displaced binding in forebrain regions than in the cerebellum. Of all drug-region combinations, only quinolinate affinity in the cerebellum was best described by a two-affinity component model (Ki = 24 and 275 microM; 45% high affinity). The cerebellum appears to contain a unique quinolinate-insensitive NMDA receptor subtype.
Department of Pharmacology, University of Nebraska Medical Center, Omaha 68198-6260.
D T
DT
Monaghan
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Beaton
D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive / Q000187:drug effects; D001923:Brain Chemistry / Q000187:drug effects*; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism*; D005971:Glutamates / Q000378:metabolism / Q000494:pharmacology; D018698:Glutamic Acid; D007051:Ibotenic Acid / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D016202:N-Methylaspartate / Q000494:pharmacology; D017378:Quinolinic Acid; D011805:Quinolinic Acids / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects*
D005971:Glutamates; D011805:Quinolinic Acids; D016194:Receptors, N-Methyl-D-Aspartate; D007051:Ibotenic Acid; D018698:Glutamic Acid; D016202:N-Methylaspartate; D017378:Quinolinic Acid