Induction of NMDA receptor-dependent long-term depression in visual cortex does not require metabotropic glutamate receptors.
We tested the role of group I mGluRs in the induction of long-term depression (LTD) in the visual cortex, using the novel mGluR antagonist LY341495 and mice lacking mGluR5, the predominant phosphoinositide (PI)-linked mGluR in the visual cortex. We find that LY341495 is a potent blocker of glutamate-stimulated PI hydrolysis in visual cortical synaptoneurosomes, and that it effectively antagonizes the actions of the mGluR agonist 1S, 3R-aminocyclopentane-1,3-dicarboxylic acid (ACPD) on synaptic transmission in visual cortical slices. However, LY341495 has no effect on the induction of LTD by low-frequency stimulation. Furthermore, mice lacking mGluR5 show normal NMDA receptor-dependent LTD. These results indicate that group I mGluR activation is not required for the induction of NMDA receptor-dependent LTD in the visual cortex.
Sawtell
N B
NB
Department of Neuroscience, Howard Hughes Medical Institute, Brown University, Providence, Rhode Island 02912, USA.
Huber
K M
KM
Roder
J C
JC
Bear
M F
MF
D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D003864:Depression, Chemical; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D006868:Hydrolysis; D066298:In Vitro Techniques; D008734:Methoxyhydroxyphenylglycol / Q000031:analogs & derivatives / Q000494:pharmacology; D051379:Mice; D018345:Mice, Knockout; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D010716:Phosphatidylinositols / Q000378:metabolism; D051381:Rats; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism; D014793:Visual Cortex / Q000187:drug effects / Q000502:physiology*; D014966:Xanthenes / Q000494:pharmacology
D000596:Amino Acids; D018691:Excitatory Amino Acid Antagonists; C114624:LY 341495; D010716:Phosphatidylinositols; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D014966:Xanthenes; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; D008734:Methoxyhydroxyphenylglycol; C010117:3,4-dihydroxyphenylglycol