Development of metabotropic glutamate receptor-mediated synaptic inhibition.
Modulation of hippocampal CA3-CA1 synaptic transmission during metabotropic glutamate receptor (mGluR) activation was investigated in juvenile (postnatal day (P) 15-21) and young adult rats (P28-35). The mGluR agonist 1S,3R-aminocyclopentane-1,3-dicarboxylic acid (ACPD) depressed the EPSP slope more in young adults than juveniles. ACPD increased paired-pulse facilitation (PPF) at both ages. The group I mGluR antagonist (+)-alpha-methylcarboxyphenylglycine (MCPG) inhibited the ACPD-mediated depression of the EPSP slope and completely blocked the increase in PPF only in young adults. Minimal effects of MCPG on ACPD-dependent synaptic depression were observed in juveniles. These data suggest that presynaptic group I mGluR-mediated synaptic inhibition increases across late postnatal development. In addition, other mGluR subtypes, with the ability to depress presynaptic function, appear to be present in juveniles.
Dumas
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Department of Psychology, University of Virginia, Charlottesville 22903, USA.
Foster
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D000818:Animals; D001565:Benzoates / Q000494:pharmacology; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D066298:In Vitro Techniques; D008297:Male; D009433:Neural Inhibition / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018094:Receptors, Metabotropic Glutamate / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*
D001565:Benzoates; D018691:Excitatory Amino Acid Antagonists; D018094:Receptors, Metabotropic Glutamate; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane; C079694:alpha-methyl-4-carboxyphenylglycine; D005998:Glycine