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Dendritic release of glutamate suppresses synaptic inhibition of pyramidal neurons in rat neocortex
Author(s) -
Zilberter Y.
Publication year - 2000
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2000.00489.x
Subject(s) - pyramidal cell , neocortex , metabotropic glutamate receptor , inhibitory postsynaptic potential , neuroscience , glutamate receptor , excitatory postsynaptic potential , chemistry , interneuron , biophysics , biology , hippocampus , receptor , biochemistry
1 Dual whole‐cell recordings were made in layer 2/3 of the rat neocortex in synaptically connected pyramidal cells and fast‐spiking non‐accommodating (FSN) interneurons. In 75% of cell pairs ( n = 80 ), the cells formed reciprocal synaptic connections. 2 Trains of backpropagating action potentials in pyramidal cells induced Ca 2+ transients in dendrites followed by inhibition of unitary IPSPs. IPSP depression was prevented by loading pyramidal cells with 5 m m BAPTA or EGTA. 3 IPSP depression was mimicked by the metabotropic glutamate receptor (mGluR) agonist ACPD and was prevented by a mixture of the mGluR antagonists CPCCOEt and EGLU. 4 IPSP depression was prevented by loading pyramidal cells with the antagonists of vesicular exocytosis botulinum toxin D (light chain) and GDP‐β‐S. 5 It is concluded that Ca 2+ ‐dependent release of a retrograde messenger, most probably glutamate, from pyramidal cell dendrites suppresses the inhibition of pyramidal neurons via activation of mGluRs located in FSN interneuron nerve terminals.