title: Use-dependent effects of amyloidogenic fragments of (beta)-amyloid precursor protein on synaptic plasticity in rat hippocampus in vivo.
abstract: The Alzheimer's disease-related beta-amyloid precursor protein (beta-APP) is metabolized to a number of potentially amyloidogenic peptides that are believed to be pathogenic. Application of relatively low concentrations of the soluble forms of these peptides has previously been shown to block high-frequency stimulation-induced long-term potentiation (LTP) of glutamatergic transmission in the hippocampus. The present experiments examined how these peptides affect low-frequency stimulation-induced long-term depression (LTD) and the reversal of LTP (depotentiation). We discovered that beta-amyloid peptide (Abeta1-42) and the Abeta-containing C -terminus of beta-APP (CT) facilitate the induction of LTD in the CA1 area of the intact rat hippocampus. The LTD was frequency- and NMDA receptor-dependent. Thus, although low-frequency stimulation alone was ineffective, after intracerebroventricular injection of Abeta1-42, it induced an LTD that was blocked by d-(-)-2-amino-5-phosphonopentanoic acid. Furthermore, an NMDA receptor-dependent depotentiation was induced in a time-dependent manner, being evoked by injection of CT 10 min, but not 1 hr, after LTP induction. These use- and time-dependent effects of the amyloidogenic peptides on synaptic plasticity promote long-lasting reductions in synaptic strength and oppose activity-dependent strengthening of transmission in the hippocampus. This will result in a profound disruption of information processing dependent on hippocampal synaptic plasticity.
authors.affiliation: Departments of Pharmacology, Trinity College, Dublin 2, Ireland.
authors.forename: J H
authors.initials: JH
authors.lastname: Kim
authors.forename: R
authors.initials: R
authors.lastname: Anwyl
authors.forename: Y H
authors.initials: YH
authors.lastname: Suh
authors.forename: M B
authors.initials: MB
authors.lastname: Djamgoz
authors.forename: M J
authors.initials: MJ
authors.lastname: Rowan
mesh_terms: D000682:Amyloid / Q000096:biosynthesis; D016229:Amyloid beta-Peptides / Q000008:administration & dosage; D016564:Amyloid beta-Protein Precursor / Q000008:administration & dosage / Q000378:metabolism*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation / Q000379:methods; D004567:Electrodes, Implanted; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism*; D007276:Injections, Intraventricular; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D009433:Neural Inhibition / Q000187:drug effects; D009473:Neuronal Plasticity / Q000187:drug effects*; D010446:Peptide Fragments / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000682:Amyloid; D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor; D018691:Excitatory Amino Acid Antagonists; D010446:Peptide Fragments; D016194:Receptors, N-Methyl-D-Aspartate; C075222:amyloid beta-protein (1-42); C409682:amyloid beta-protein precursor CT105