Biphasic effect of quinolinate on frog spinal, but not rat cortical, neurones: N-methyl-D-aspartate-like depolarisation and a novel type of hyperpolarisation.
Using grease seal techniques on rat cerebral cortical slices and on frog hemisected spinal cords, bath applied N-methyl-D-aspartate (NMDA; 10-160 microM) and quinolinate (0.25-8 mM) induced dose-dependent depolarisations. These depolarising responses, but not those to quisqualate or kainate, were reduced by 2-amino-5-phosphono-valerate (2-AP5; 10-100 microM), magnesium (0.1-10 mM) and ketamine (10-100 microM). A novel dose-dependent hyperpolarising response to quinolinate (0.1-2 mM) but not to NMDA was observed only on frog motoneurones, and this was not reduced by classical amino acid receptor antagonists.
D015763:2-Amino-5-phosphonovalerate; D000818:Animals; D000870:Anterior Horn Cells / Q000187:drug effects*; D001001:Anura; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D004347:Drug Interactions; D006179:Gyrus Cinguli / Q000187:drug effects*; D007608:Kainic Acid / Q000494:pharmacology; D007649:Ketamine / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009046:Motor Neurons / Q000187:drug effects*; D016202:N-Methylaspartate; D011725:Pyridines / Q000494:pharmacology*; D017378:Quinolinic Acid; D011805:Quinolinic Acids / Q000494:pharmacology*; D051381:Rats; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
D011725:Pyridines; D011805:Quinolinic Acids; D001224:Aspartic Acid; D016202:N-Methylaspartate; D007649:Ketamine; D015763:2-Amino-5-phosphonovalerate; D017378:Quinolinic Acid; D014633:Valine; D008274:Magnesium; D007608:Kainic Acid