(R,S)-alpha-methyl-4-carboxyphenylglycine (MCPG) blocks spatial learning in rats and long-term potentiation in the dentate gyrus in vivo.
Recently, it was demonstrated by the use of the competitive and selective antagonist (R,S)-alpha-methyl-4-carboxyphenylglycine (MCPG) that metabotropic glutamate receptor (mGluR) activation is required to induce long-term potentiation (LTP) in the hippocampus. Accordingly, we investigated whether MCPG also inhibits spatial learning. Rats were trained on a spatial alternation task in a Y-maze with footshock reinforcement, and MCPG (0.0208 mg) was injected intracerebroventricularly prior to training and/or retention test. Animals injected pre-training are clearly impaired in retention, whereas preretention application was without effect. A state dependency could be excluded. Additionally, MCPG at the same concentration completely blocks a potentiation at perforant path/dentate gyrus synapses in vivo. These results strongly implicate a role of mGluRs in spatial learning and LTP.
Riedel
G
G
Department of Neurophysiology, Institute for Neurobiology, Magdeburg, Germany.
Wetzel
W
W
Reymann
K G
KG
D000818:Animals; D001565:Benzoates / Q000008:administration & dosage / Q000494:pharmacology*; D004597:Electroshock; D005528:Foot; D005998:Glycine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology*; D007276:Injections, Intraventricular; D007858:Learning / Q000187:drug effects*; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors; D012054:Reinforcement, Psychology; D012153:Retention, Psychology / Q000187:drug effects; D013037:Spatial Behavior / Q000187:drug effects*
D001565:Benzoates; D018094:Receptors, Metabotropic Glutamate; C079694:alpha-methyl-4-carboxyphenylglycine; D005998:Glycine