Original Paper

Developmental Regulation of the Distribution of Aromatase- and Estrogen-Receptor- mRNA-Expressing Cells in the Zebra Finch Brain
Erin C. Jacobs^a, Arthur P. Arnold^b, Anthony T. Campagnoni<sup>c

a</sup>Program in Neuroscience,
^bDepartment of Physiological Science and the Laboratory of Neuroendocrinology,
^cMental Retardation Research Center and Department of Psychiatry, University of California, Los Angeles, Calif., USA

Address of Corresponding Author

Dev Neurosci 1999;21:453-472 (DOI: 10.1159/000017413)

  Key Words

• Aromatase
• Development
• Estrogen
• In situ hybridization
• Song system
• Zebra finch

  Abstract

Strong evidence exists for the masculinizing effects of estrogen on the neural network that controls song learning and behavior in zebra finches. However, the mechanisms by which estrogen acts to influence the development of this circuitry are not well understood. In this study, we used in situ hybridization to detect the distribution of cells expressing mRNAs for AROM and ER at postnatal days 5-25 (P5-25). Our findings revealed developmental regulation of both mRNAs in the neostriatum, archistriatum, hippocampus, diencephalon and midbrain. Within the vocal control circuitry, cells expressing ER mRNA were found in the medial HVC (P10-25), archistriatum lateral to the RA (Ad; P25), in the ICo (P5-25), and along the fiber tract containing efferents from the RA. High levels of AROM mRNA were found in the neostriatum, including both the lateral and mMAN and along their projections to the RA and HVC, respectively, (P5-25), in the archistriatum (P18-25) and around RA (P18). Codistribution of the two mRNAs occurred along the border of the HVC suggesting that in this region, local synthesis of estrogen may be acting through its nuclear receptor to regulate gene transcription. Taken together, our findings show that the neural circuitry controlling song may be exposed to the effects of estrogen during early postnatal development. However, in most of the song control regions, these mRNAs were not expressed together either temporally or spatially, indicating that AROM may have a role in the development of the song system independent of ER.

Copyright © 2000 S. Karger AG, Basel

  Author Contacts

Anthony T. Campagnoni
Mental Retardation Research Center, 47-448 NPI, UCLA School of Medicine
760 Westwood Plaza
Los Angeles, CA 90024-17519 (USA)
Tel. +1 310 825 5006, Fax +1 310 206 5050, E-Mail acampagnoni@mednet.ucla.edu

  Article Information

Received: Received: July 9, 1999
Accepted: July 28, 1999
Number of Print Pages : 20
Number of Figures : 8, Number of Tables : 1, Number of References : 89