Modulation of memory processing by glutamic acid receptor agonists and antagonists.
Recent hypotheses suggesting a critical role of glutamate receptors in hippocampal long-term potentiation and memory processing suggested a closer examination of this transmitter's effect on memory processing in an in vivo setting. New pharmacological antagonists allow for a separation and examination of various glutamate receptors and their role in memory processing. Mice were trained on a shock avoidance learning paradigm and injected intracerebroventricularly after training with agonists and antagonists of various classes of glutamate receptors. Retention was tested 1 week after training. N-Methyl-D-aspartate (NMDA) receptor agonists enhanced retention in a dose-dependent manner. The enhancement of retention by the non-NMDA agonist kainic acid and quisqualic acid was dose-dependent. L-Glutamic acid, but not D-glutamic acid, enhanced retention. Both NMDA and non-NMDA receptor antagonists produced dose-dependent impairment of retention for footshock training. Administration of the antagonists 24 h after training did not impair memory retention.
Flood
J F
JF
Geriatric Research, Education and Clinical Center, Veterans Administration Hospital, St. Louis, MO 63106.
Baker
M L
ML
Davis
J L
JL
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D007276:Injections, Intraventricular; D008297:Male; D008568:Memory / Q000187:drug effects*; D051379:Mice; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism / Q000502:physiology; D017981:Receptors, Neurotransmitter / Q000187:drug effects / Q000502:physiology*
D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter