Coincidence detection and changes of synaptic efficacy in spiny stellate neurons in rat barrel cortex.
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.
Egger
V
V
Abteilung Zellphysiologie, Max-Planck-Institut für medizinische Forschung, Jahnstr. 29, D-69120 Heidelberg, Germany.
Feldmeyer
D
D
Sakmann
B
B
D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D018698:Glutamic Acid / Q000378:metabolism; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D009473:Neuronal Plasticity / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology; D051381:Rats; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000502:physiology; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000502:physiology; D013003:Somatosensory Cortex / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D013873:Thionucleotides / Q000494:pharmacology; D013997:Time Factors
D002614:Chelating Agents; D018091:Receptors, AMPA; D018094:Receptors, Metabotropic Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D013873:Thionucleotides; C108822:metabotropic glutamate receptor 2; C102718:metabotropic glutamate receptor 3; D006153:Guanosine Diphosphate; D018698:Glutamic Acid; C023427:guanosine 5'-O-(2-thiodiphosphate); D002118:Calcium