title: Postsynaptic signals mediating induction of long-term synaptic depression in the entorhinal cortex.
abstract: The entorhinal cortex receives a large projection from the piriform cortex, and synaptic plasticity in this pathway may affect olfactory processing. In vitro whole cell recordings have been used here to investigate postsynaptic signalling mechanisms that mediate the induction of long-term synaptic depression (LTD) in layer II entorhinal cortex cells. To induce LTD, pairs of pulses, using a 30-millisecond interval, were delivered at 1 Hz for 15 minutes. Induction of LTD was blocked by the NMDA receptor antagonist APV and by the calcium chelator BAPTA, consistent with a requirement for calcium influx via NMDA receptors. Induction of LTD was blocked when the FK506 was included in the intracellular solution to block the phosphatase calcineurin. Okadaic acid, which blocks activation of protein phosphatases 1 and 2a, also prevented LTD. Activation of protein phosphatases following calcium influx therefore contributes to induction of LTD in layer II of the entorhinal cortex.
authors.affiliation: Center for Studies in Behavioral Neurobiology, Department of Psychology, Concordia University, Montréal, QC, Canada.
authors.forename: Saïd
authors.initials: S
authors.lastname: Kourrich
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Glasgow
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Caruana
authors.forename: C Andrew
authors.initials: CA
authors.lastname: Chapman
mesh_terms: D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D019703:Calcineurin / Q000502:physiology; D020013:Calcium Signaling; D016572:Cyclosporine / Q000494:pharmacology; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018728:Entorhinal Cortex / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D036881:Long-Term Synaptic Depression / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D019319:Okadaic Acid / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D054645:Protein Phosphatase 1 / Q000502:physiology; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D016559:Tacrolimus / Q000494:pharmacology
chemical_list: D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D019319:Okadaic Acid; D016291:Dizocilpine Maleate; D015763:2-Amino-5-phosphonovalerate; D016572:Cyclosporine; D019703:Calcineurin; D054645:Protein Phosphatase 1; D016559:Tacrolimus