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Estrogen produced in cultured hippocampal neurons is a functional regulator of a GABAergic machinery
Author(s) -
Ikeda Takamitsu,
Matsuki Norio,
Yamada Maki K.
Publication year - 2006
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.21083
Subject(s) - glutamate decarboxylase , gabaergic , hippocampal formation , aromatase , medicine , brain derived neurotrophic factor , endocrinology , estrogen , biology , gamma aminobutyric acid , estrogen receptor beta , estrogen receptor , neurotransmission , glutamate receptor , neurotrophic factors , receptor , enzyme , biochemistry , inhibitory postsynaptic potential , cancer , breast cancer
Accumulating evidence suggests that estrogen is produced locally by the neurons in the brain. We observed that a 48‐hr treatment with the estrogen receptor antagonists ICI 182780 and tamoxifen decreased the level of glutamate decarboxylase (GAD)‐65, a rate‐limiting γ‐aminobutyric acid (GABA)‐synthesizing enzyme, in a dissociated hippocampal neuronal culture. Aromatase is an essential enzyme for estrogen biosynthesis. Treatment with an aromatase inhibitor decreased the GAD 65 level, indicating that estrogen biogenesis functions to maintain the level of this enzyme for GABAergic neurotransmission. Furthermore, insofar as the effect of ICI 182780 was observed equivalently in the presence of either brain‐derived neurotrophic factor (BDNF) or BDNF‐receptor inhibitor K252a, estrogen probably regulates GAD level independently of brain‐derived neurotrophic factor (BDNF). Thus, estrogen produced by neurons is considered to be an intrinsic regulatory factor for neuronal networks that maintain GABAergic neurotransmission. © 2006 Wiley‐Liss, Inc.