Brain aromatase: new lessons from non-mammalian model systems

Area of Science:

• Neuroendocrinology
• Comparative Neurobiology
• Behavioral Neuroscience

Background:

• Brain aromatase (estrogen synthase) plays a crucial role in local estrogen synthesis within the brain.
• Teleost fishes and songbirds exhibit exceptionally high levels of brain aromatase activity, protein, and gene expression compared to other vertebrates.
• These species serve as valuable neuroethological models for studying the impact of local estrogen synthesis on neural phenotypes and behavior.

Purpose of the Study:

• To review the anatomical and functional implications of brain aromatase expression in teleost fishes and songbirds.
• To explore how region-specific estrogen synthesis influences neural circuits and behavior in these vertebrates.
• To understand the neuroendocrine system's capacity for temporal and spatial specificity in behavioral modulation via targeted estrogen synthesis.

Main Methods:

• Review of recent studies on brain aromatase expression (activity, protein, gene).
• Analysis of neuroethological data from teleost fishes and songbirds.
• Examination of region-specific patterns of aromatase expression in vocal and auditory circuits.

Main Results:

• Teleosts and songbirds demonstrate high adult brain aromatase activity, protein, and gene expression.
• Aromatase expression is notably concentrated in vocal and auditory circuits, crucial for species-specific behaviors.
• Local estrogen synthesis allows for targeted modulation of neural circuits, influencing specific behaviors like vocalization.

Conclusions:

• High brain aromatase expression in teleosts and songbirds facilitates localized estrogen synthesis.
• Region-specific estrogen synthesis, particularly in vocal/auditory circuits, is key to behavioral adaptations.
• The neuroendocrine system can precisely control behavior by targeting specific neural circuits through localized estrogen production.