Induction of cerebellar long-term depression requires activation of glutamate metabotropic receptors.
In rat cerebellar slices, 500 microM (RS)-alpha-methyl-4-carboxyphenylglycine (MCPG) reversibly inhibited both dendritic and somatic increases in FLUO-3 fluorescence intensity induced by bath applications of 50-100 microM (+-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid (t-ACPD). No effect of MCPG was observed on dendritically recorded excitatory postsynaptic potentials evoked by synaptic activation of either parallel or climbing fibres. Long-term depression of parallel fibre-Purkinje cell transmission, induced either by conjunctive activation of parallel and climbing fibres or by pairing parallel fibre stimulation with intradendritic injections of 8-BrcGMP, was not only prevented in the presence of MCPG but a robust long-term potentiation of responses consistently occurred. These data show that metabotropic glutamate receptor activation is necessary for the induction of LTD.
Hartell
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NA
Laboratory for Neural Networks, Frontier Research Program, RIKEN, Saitama, Japan.
D000814:Aniline Compounds; D000818:Animals; D001565:Benzoates / Q000494:pharmacology; D001711:Biotransformation / Q000187:drug effects / Q000502:physiology; D002531:Cerebellum / Q000187:drug effects / Q000502:physiology*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D003521:Cyclopropanes; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D005456:Fluorescent Dyes; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D009498:Neurotoxins / Q000494:pharmacology; D011689:Purkinje Cells / Q000187:drug effects / Q000502:physiology; D051381:Rats; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology; D014966:Xanthenes
D000814:Aniline Compounds; D001565:Benzoates; D003521:Cyclopropanes; D005456:Fluorescent Dyes; D009498:Neurotoxins; D018094:Receptors, Metabotropic Glutamate; D014966:Xanthenes; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; C079694:alpha-methyl-4-carboxyphenylglycine; C059715:Fluo-3; C016276:8-bromocyclic GMP; D006152:Cyclic GMP; D005998:Glycine