title: Estrogen induces rapid decrease in dendritic thorns of CA3 pyramidal neurons in adult male rat hippocampus.
abstract: Modulation of hippocampal synaptic plasticity by estrogen has been attracting much attention. Thorns of thorny excrescences of CA3 hippocampal neurons are post-synaptic regions whose presynaptic partners are mossy fiber terminals. Here we demonstrated the rapid effect of estradiol on the density of thorns of thorny excrescences, by imaging Lucifer Yellow-injected CA3 neurons in adult male rat hippocampal slices. The application of 1nM estradiol induced rapid decrease in the density of thorns on pyramidal neurons within 2h. The estradiol-mediated decrease in the density of thorns was blocked by CNQX (AMPA receptor antagonist) and PD98059 (MAP kinase inhibitor), but not by MK-801 (NMDA receptor antagonist). ERalpha agonist PPT induced the same suppressive effect as that induced by estradiol on the density of thorns, but ERbeta agonist DPN did not affect the density of thorns. Note that a 1nM estradiol treatment did not affect the density of spines in the stratum radiatum and stratum oriens. A search for synaptic ERalpha was performed using purified RC-19 antibody. The localization of ERalpha (67kDa) in the CA3 mossy fiber terminals and thorns was demonstrated using immunogold electron microscopy. These results imply that estradiol drives the signaling pathway including ERalpha and MAP kinase.
authors.affiliation: Department of Biophysics and Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo at Komaba, 3-8-1 Meguro, Tokyo 153, Japan.
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Tsurugizawa
authors.forename: Hideo
authors.initials: H
authors.lastname: Mukai
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Tanabe
authors.forename: Gen
authors.initials: G
authors.lastname: Murakami
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Hojo
authors.forename: Shiro
authors.initials: S
authors.lastname: Kominami
authors.forename: Kenji
authors.initials: K
authors.lastname: Mitsuhashi
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Komatsuzaki
authors.forename: John H
authors.initials: JH
authors.lastname: Morrison
authors.forename: William G M
authors.initials: WG
authors.lastname: Janssen
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kimoto
authors.forename: Suguru
authors.initials: S
authors.lastname: Kawato
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D003712:Dendrites / Q000187:drug effects* / Q000648:ultrastructure; D004967:Estrogens / Q000494:pharmacology*; D006624:Hippocampus / Q000166:cytology* / Q000187:drug effects* / Q000648:ultrastructure; D008297:Male; D016253:Microscopy, Immunoelectron; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D004967:Estrogens