Comparison of kynurenic acid and 2-APV suppression of epileptiform activity in rat hippocampal slices.
The N-methyl-D-aspartate (NMDA) receptor blocker 2-amino-5-phosphonovaleric acid [+/-)-2-APV) and kynurenic acid both suppressed spontaneous epileptiform burst discharges in the CA3 region of rat hippocampal slices. When the bursts were induced by perfusion with magnesium-free medium (+/-)-2-APV was the more potent inhibitor (ED50 66 microM for (+/-)-2-APV and 110 microM for kynurenate). When bursts were induced by picrotoxin, kynurenate was more potent with an ED50 of 132 microM, compared with 290 microM for (+/-)-2-APV. Both antagonists were selective inhibitors of responses to NMDA when examined against excitations induced by NMDA, kainate and quisqualate applied by microiontophoresis onto CA3 pyramidal cells. The results may indicate a complex receptor profile for endogenous compounds involved in epileptiform bursts, or the existence of non-pyramidal cells bearing non-NMDA receptors sensitive to kynurenic acid.
D015763:2-Amino-5-phosphonovalerate; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D004827:Epilepsy / Q000503:physiopathology*; D006624:Hippocampus / Q000187:drug effects / Q000503:physiopathology*; D066298:In Vitro Techniques; D007736:Kynurenic Acid / Q000494:pharmacology*; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D014633:Valine / Q000031:analogs & derivatives* / Q000494:pharmacology
D015763:2-Amino-5-phosphonovalerate; D007736:Kynurenic Acid; D014633:Valine