Seasonal changes in the densities of α2-noradrenergic receptors are inversely related to changes in testosterone and the volumes of song control nuclei in male European starlings

Lauren V. Riters, Rianne Pinxten, Marcel Eens, Gregory F. Ball

Research output: Contribution to journalArticle

Abstract

The functions of song and the contextual cues that elicit song change seasonally in parallel with testosterone (T) concentrations in male European starlings. T is high in spring when at least one function of male song is that of immediate mate attraction, and low outside the context of breeding, when starlings primarily use song for dominance or flock maintenance. Several brain nuclei that control song contain high densities of α2-adrenergic receptors. T can regulate the density of α2-adrenergic receptors in the avian brain, indicating that the density of α2-adrenergic receptors within the song system might change seasonally. Although the function of seasonal brain variation is not entirely clear, in many songbirds the volumes of song nuclei are largest when T is high and males sing most. Male starlings, however, sing both when T is high and when T is low. Therefore, exploring seasonal changes in T and the volumes of song nuclei could provide insight into the function of these changes. The present study was performed to explore the relationships among T, the volumes of song nuclei, and the densities of α2-adrenergic receptors within the song system of male starlings. Song nuclei (the high vocal center [HVc], robust nucleus of the archistriatum [RA], and Area X) were largest, T was highest, and the density of α2-adrenergic receptors (within HVc and RA) was lowest during the breeding season. The reverse pattern was observed outside of the breeding season. These results suggest that changes in T, volumes of song nuclei, and α2-receptor densities might regulate seasonal changes in song behavior or the context that will elicit song in male starlings.

Original languageEnglish (US)
Pages (from-to)63-74
Number of pages12
JournalJournal of Comparative Neurology
Volume444
Issue number1
DOIs
Publication statusPublished - Feb 25 2002
Externally publishedYes

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Keywords

  • Neural plasticity
  • Norepinephrine
  • Seasonality
  • Song control system
  • Songbird

ASJC Scopus subject areas

  • Neuroscience(all)

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