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Distribution of estrogen receptor alpha mRNA in the brain and inner ear of a vocal fish with comparisons to sites of aromatase expression
Author(s) -
Forlano Paul M.,
Deitcher David L.,
Bass Andrew H.
Publication year - 2005
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.20397
Subject(s) - biology , estrogen receptor , aromatase , forebrain , medicine , estrogen , endocrinology , estrogen receptor alpha , inferior colliculus , midbrain , estrogen receptor beta , preoptic area , hypothalamus , central nervous system , neuroscience , nucleus , genetics , cancer , breast cancer
Abstract Among vertebrates, teleost fish have the greatest capacity for estrogen production in the brain. Previously, we characterized the distribution of the estrogen‐synthesizing enzyme aromatase in the brain of the midshipman fish. Here, we investigated the distribution of estrogen receptor alpha (ERα). A partial cDNA of ERα was cloned and used to generate midshipman‐specific primers for RT and real‐time PCR which identified transcripts in liver and ovary, the CNS, and the sensory epithelium of the main auditory endorgan (sacculus). In situ hybridization revealed abundant expression throughout the preoptic area, a vocal‐acoustic site in the hypothalamus, amygdala homologs of the dorsal pallium, the pineal organ, the inner ear, the pituitary, and the ovary. Weaker expression was found in the midbrain's nucleus of the medial longitudinal fasciculus and in the dimorphic vocal motor nucleus. ERα expression in the pineal, gonad, and pituitary axis may function to time seasonal abiotic cues to reproductive state, while expression in the vocal motor and auditory systems support neurophysiological evidence for estrogen as a modulator of vocal motor and auditory encoding mechanisms in midshipman fish. While ERα is restricted to specific nuclei, aromatase expression is abundant in glial cells throughout the entire forebrain, and high in midbrain and hindbrain – spinal vocal regions. The only site of aromatase‐containing neurons is in the peripheral auditory system, where it is localized to ganglion cells in the auditory nerve. Estrogen production proximal to ERα‐positive neurons may provide for focal sites of estrogen effects on reproductive‐, vocal‐, and auditory‐related neurons. J. Comp. Neurol. 483:91–113, 2005. © 2005 Wiley‐Liss, Inc.