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Receptors and Second Messengers Involved in Long‐term Depression in Rat Cerebellar Slices In Vitro: a Reappraisal
Author(s) -
Hémart Nathalie,
Daniel Hervé,
Jaillard Danielle,
Crépel Francis
Publication year - 1995
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1995.tb01019.x
Subject(s) - cnqx , metabotropic glutamate receptor , long term depression , metabotropic receptor , ionotropic effect , nmda receptor , ampa receptor , glutamate receptor , chemistry , neuroscience , metabotropic glutamate receptor 1 , biophysics , pharmacology , microbiology and biotechnology , biology , receptor , biochemistry
In patch‐clamped Purkinje cells (PCs), bath application of the ionotropic glutamate receptor antagonist, 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione (CNQX) prevents induction of long‐term depression (LTD) of parallel fibre (PF)‐mediated EPSPs by a pairing protocol between Ca 2+ spike firing and PF stimulation whereas bath application of ( RS )‐α‐methyl‐4‐carboxyphenylglycine (MCPG), a metabotropic glutamate (mGLU) receptor antagonist, does not. On the other hand, LTD can be also induced by pairing direct depolarization of PCs with activation of mGLU receptors by 1 S,3 R ‐aminocyclopentyl‐dicarboxylate (1S, 3 R ‐ACPD), even in the presence of CNQX. In this case, LTD induction is not consistently blocked by bath application of the nitric oxide synthase inhibitor, N G ‐methyl‐ l ‐arginine ( l ‐NMMA), whereas it is strongly blocked when the protein kinase C inhibitor peptide 19‐36 is dialysed into PCs. These results are at variance with LTD induced by a pairing protocol between Ca 2+ spikes and PF‐mediated EPSPs which depends to the same extent on both cascades. Finally, thapsigargin, which depletes most intracellular Ca 2+ pools, does not block induction of LTD by a pairing protocol between Ca 2+ spikes and PF‐mediated EPSPs whereas it prevents the induction of LTD depending on strong mGLU receptor activation.