Abstract
Paired whole-cell voltage recordings were made from synaptically connected spiny stellate neurons in layer 4 of the barrel field in young (P14) rat somatosensory cortex. When postsynaptic action potentials (APs) followed each of 5 presynaptic APs in a 10- or 20-Hz train by less than 25 ms, subsequent unitary EPSP amplitudes were persistently reduced. Induction of long-term depression (LTD) depended on activation of group II metabotropic glutamate receptors, but not on NMDA or AMPA receptors. Reducing postsynaptic increases in intracellular calcium ([Ca2+]i) by intracellular loading with a fast- (BAPTA) or a slow- (EGTA) acting Ca2+ buffer blocked synaptic depression. Analysis of EPSP failures suggested mediation of LTD by a reduction in release probability. We propose a mechanism by which coincident activity results in long-lasting reduction of synaptic efficacy between synaptically connected neurons.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
Calcium / antagonists & inhibitors
-
Calcium / metabolism
-
Calcium / pharmacology
-
Chelating Agents / pharmacology
-
Electric Stimulation
-
Excitatory Postsynaptic Potentials / drug effects
-
Excitatory Postsynaptic Potentials / physiology*
-
Glutamic Acid / metabolism
-
Guanosine Diphosphate / analogs & derivatives
-
Guanosine Diphosphate / pharmacology
-
In Vitro Techniques
-
Neuronal Plasticity / drug effects
-
Neurons / drug effects
-
Neurons / physiology*
-
Pyramidal Cells / drug effects
-
Pyramidal Cells / physiology
-
Rats
-
Receptors, AMPA / antagonists & inhibitors
-
Receptors, AMPA / physiology
-
Receptors, Metabotropic Glutamate / agonists
-
Receptors, Metabotropic Glutamate / antagonists & inhibitors
-
Receptors, Metabotropic Glutamate / physiology
-
Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
-
Receptors, N-Methyl-D-Aspartate / physiology
-
Somatosensory Cortex / cytology
-
Somatosensory Cortex / drug effects
-
Somatosensory Cortex / physiology*
-
Synapses / drug effects
-
Synapses / physiology*
-
Synaptic Transmission / drug effects
-
Synaptic Transmission / physiology*
-
Thionucleotides / pharmacology
-
Time Factors
Substances
-
Chelating Agents
-
Receptors, AMPA
-
Receptors, Metabotropic Glutamate
-
Receptors, N-Methyl-D-Aspartate
-
Thionucleotides
-
metabotropic glutamate receptor 2
-
metabotropic glutamate receptor 3
-
Guanosine Diphosphate
-
Glutamic Acid
-
guanosine 5'-O-(2-thiodiphosphate)
-
Calcium