title: Calcineurin inhibitors, FK506 and cyclosporin A, suppress the NMDA receptor-mediated potentials and LTP, but not depotentiation in the rat hippocampus.
abstract: The effects of FK506, a Ca2+/calmodulin-dependent phosphatase 2B (calcineurin) inhibitor, on the NMDA receptor-mediated potentials and synaptic plasticity were investigated in the CA1 region of the rat hippocampus. Bath application of FK506 (50 microM) produced a 45% inhibition on the NMDA receptor-mediated potentials. FK506 also inhibited the induction of long-term potentiation (LTP), but had no effect on the depotentiation in the CA1 hippocampus. Cyclosporin A (100 microM), another calcineurin inhibitor, mimicked the effects of FK506 on the NMDA responses and synaptic plasticity. These results suggest that FK506 inhibits the activity of NMDA receptors via the involvement of calcineurin. The differential effects of FK506 on LTP and depotentiation may attribute to the partial inhibition on the activity of NMDA receptors and the subsequent attenuation of intracellular Ca2+ increase.
authors.affiliation: First Department of Physiology, Okayama University Medical School, Japan.
authors.forename: Y F
authors.initials: YF
authors.lastname: Lu
authors.forename: K
authors.initials: K
authors.lastname: Tomizawa
authors.forename: A
authors.initials: A
authors.lastname: Moriwaki
authors.forename: Y
authors.initials: Y
authors.lastname: Hayashi
authors.forename: M
authors.initials: M
authors.lastname: Tokuda
authors.forename: T
authors.initials: T
authors.lastname: Itano
authors.forename: O
authors.initials: O
authors.lastname: Hatase
authors.forename: H
authors.initials: H
authors.lastname: Matsui
mesh_terms: D000818:Animals; D019703:Calcineurin; D002148:Calmodulin-Binding Proteins / Q000037:antagonists & inhibitors*; D016572:Cyclosporine / Q000494:pharmacology*; D003864:Depression, Chemical; D004353:Drug Evaluation, Preclinical; D005071:Evoked Potentials / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects*; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects; D008297:Male; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D016559:Tacrolimus / Q000494:pharmacology*
chemical_list: D002148:Calmodulin-Binding Proteins; D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D016572:Cyclosporine; D019703:Calcineurin; D010749:Phosphoprotein Phosphatases; D016559:Tacrolimus