2R,4R-4-Aminopyrrolidine-2,4-dicarboxylate (APDC) attenuates cortical EPSPs.
We studied the effect of the Type II metabotropic glutamate receptor (mGluR 2,3) agonist APDC on the response of neurons in slices of rat visual cortex. In all cortical layers, APDC attenuated the EPSP produced by stimulation of the predominant excitatory input. This EPSP attenuation was seen in both younger and older rat slices and was present with G-protein blockade in the cell recorded, demonstrating that it was a presynaptic effect. Further, this EPSP attenuation was blocked by the mGluR 2,3 antagonist EGLU. A postsynaptic depressive effect of APDC on the NMDA response was seen in layers 2 and 3, but not in layers 5 and 6. Thus, the predominant action of Type II mGluRs in the visual cortex is a presynaptic reduction of glutamate release which persists through development. This regulation may be important in the setting of excitatory tone in visual cortex and in the extraction/processing of visual information.
Flavin
H J
HJ
Department of Ophthalmology and Visual Science, Yale University School of Medicine, 330 Cedar Street, P.O. Box 20-8061, New Haven, CT 06520-8061, USA.
Jin
X T
XT
Daw
N W
NW
D000818:Animals; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011392:Proline / Q000031:analogs & derivatives* / Q000494:pharmacology; D051381:Rats; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000187:drug effects* / Q000378:metabolism; D013569:Synapses / Q000187:drug effects / Q000378:metabolism; D014793:Visual Cortex / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
C097299:4-aminopyrrolidine-2,4-dicarboxylic acid; D018690:Excitatory Amino Acid Agonists; D018094:Receptors, Metabotropic Glutamate; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3; D011392:Proline