Estrogen induces rapid decrease in dendritic thorns of CA3 pyramidal neurons in adult male rat hippocampus.
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.
Tsurugizawa
Tomokazu
T
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.
Mukai
Hideo
H
Tanabe
Nobuaki
N
Murakami
Gen
G
Hojo
Yasushi
Y
Kominami
Shiro
S
Mitsuhashi
Kenji
K
Komatsuzaki
Yoshimasa
Y
Morrison
John H
JH
Janssen
William G M
WG
Kimoto
Tetsuya
T
Kawato
Suguru
S
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
D004967:Estrogens