Use of PG-21 immunocytochemistry to detect androgen receptors in the songbird brain.

Smith, G. Troy; Brenowitz, Eliot A.; Prins, Gail S.

doi:10.1177/44.9.8773574

Cited by 65 publications

(62 citation statements)

References 26 publications

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“…Steroid accumulation, immunocytochemical, and in situ hybridization studies show that area X neurons have few or no AR (Arnold et al, 1976;Balthazart et al, 1992;Smith et al, 1996;Bernard et al, 1999;Metzdorf et al, 1999).…”

Section: Discussionmentioning

confidence: 98%

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Afferent Input Is Necessary for Seasonal Growth and Maintenance of Adult Avian Song Control Circuits

Brenowitz

Lent

2001

J. Neurosci.

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The neural circuits that regulate song behavior in adult songbirds undergo pronounced seasonal changes in morphology, primarily in response to changes in plasma testosterone (T). Most song nuclei have T receptors. We asked whether seasonal growth and maintenance of nuclei within these circuits are direct responses to the effects of T or its metabolites or are mediated indirectly via the effects of T on afferent nuclei. Photosensitive white-crowned sparrows were exposed to one of three treatments. (1) The neostriatal nucleus HVc (also known as the "high vocal center") was lesioned unilaterally, and the birds were exposed to long-day (LD) photoperiods and breeding levels of T for 30 d. (2) Birds were exposed to LD plus T (LDϩT) for 30 d; then HVc was lesioned, and the birds were killed after an additional 30 d exposure to LDϩT. (3) HVc was lesioned, and the sparrows were housed on short-day (SD) photoperiods in the absence of T treatment for 30 d. In both LDϩT groups, the direct efferent targets of HVc, the robust nucleus of the archistriatum (RA) and area X, were smaller ipsilateral to the lesion. The lesion did not prevent growth of the hypoglossal motor nucleus, which does not receive direct afferent input from HVc. RA and area X were also smaller ipsilateral to the lesion in the SD birds. These results indicate that afferent input is required both for the growth of adult song circuits in response to typical breeding photoperiod and hormone conditions and for the maintenance of efferent nuclei in either their regressed or enlarged states.

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Section: Discussionmentioning

confidence: 98%

“…Neurons in RA of intact birds have high levels of AR (Smith et al, 1996). In the absence of afferent input from HVc, however, high plasma T concentrations were not sufficient to induce or maintain growth of RA.…”

Section: Discussionmentioning

confidence: 99%

Afferent Input Is Necessary for Seasonal Growth and Maintenance of Adult Avian Song Control Circuits

Brenowitz

Lent

2001

J. Neurosci.

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“…Experiments have focused on the HVC because it is the first song control nucleus to grow in response to elevated systemic T , and because it expresses estrogen receptors (ER) (Figure 1; Gahr et al, 1993;Bernard et al, 1999;Metzdorf et al, 1999;Fusani et al, 2000). Androgen receptors (AR) or their mRNA are expressed in every song control nucleus and the syrinx, the avian vocal organ (Fig 1; Arnold et al, 1976;Gahr et al, 1993;Nastiuk and Clayton, 1995;Smith et al, 1996;Bernard et al, 1999;Metzdorf et al, 1999;Soma et al, 1999b;Fusani et al, 2000;Kim et al, 2004). AR immunoreactivity is elevated in the HVC of Gambel's white-crowned sparrows captured in the spring; AR immunoreactivity in other song control nuclei was not quantified (Soma et al, 1999b).…”

Section: Mechanisms Of Growth Photoperiod Increases Plasma T Levelmentioning

confidence: 99%

“…Lesions of HVC prevented the growth of nXIIts (Brenowitz and Lent, 2001). Since both nXIIts and the syrinx contain AR (Smith et al, 1996), one reasonable hypothesis is that androgens act individually and directly on them to increase growth. Other hypotheses include but are not limited to: (1) retrograde support of nXIIts growth from the syrinx, (2) afferent support of nXIIts from either or both RA, and the dorsomedial portion of the intercollicular nucleus (ICo), which both contain AR, and (3) afferent support of syringeal growth from nXIIts.…”

Section: Do Androgens Act Directly On Nxiits and The Syrinx?mentioning

confidence: 99%

Seasonal-like growth and regression of the avian song control system: Neural and behavioral plasticity in adult male Gambel’s white-crowned sparrows

Meitzen

Thompson

2008

General and Comparative Endocrinology

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Birdsong is regulated by a series of discrete brain nuclei known as the song control system. In seasonally-breeding male songbirds, seasonal changes in steroid sex hormones regulate the structure and electrophysiology of song control system neurons, resulting in dramatic changes in singing behavior. Male songbirds can be brought into the laboratory, where circulating levels of steroid hormone and photoperiod can be abruptly manipulated, providing controlled conditions under which rapid "seasonal-like" changes in behavior and morphology can be carefully studied. In this minireview, we will discuss the steroidal and cellular mechanisms underlying seasonal-like growth and regression of the song control system in adult male Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii), and its impact on song behavior. Specifically, we discuss recent advances concerning: 1) the role of androgen and estrogen receptors in inducing seasonal-like growth of the song control system; 2) how photoperiod modulates the time course of testosterone-induced growth of the song control system; 3) how bilateral intracerebral infusion of androgen and estrogen receptor antagonists near the song control nucleus HVC prevents seasonal-like increases in song stereotypy but not song rate; and 4) the steroidal and cellular mechanisms that mediate rapid regression of the song control system. Throughout this mini-review we compare data collected from white-crowned sparrows to that from other songbird species. We conclude by outlining avenues of future research.

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“…38). This result is consistent with the observation that Value shown for the first time point is median (interquartile range).…”

Section: )mentioning

confidence: 99%

Act locally and think globally: Intracerebral testosterone implants induce seasonal-like growth of adult avian song control circuits

Brenowitz

Lent

2002

Proc. Natl. Acad. Sci. U.S.A.

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There is pronounced seasonal plasticity in the morphology of the neural circuits that regulate song behavior in adult songbirds, primarily in response to changes in plasma testosterone (T) levels. Most song nuclei have androgen receptors. Afferent input from the telencephalic nucleus HVc (also known as the ''high vocal center'') is necessary for seasonal growth of the direct efferent target nuclei RA and area X. We asked here whether T-stimulated growth of HVc is sufficient to induce growth of its efferent nuclei. Intracerebral T implants were placed unilaterally near HVc or RA in photosensitive adult male white-crowned sparrows for one month. The T implant near HVc produced significant growth of the ipsilateral (but not contralateral) HVc, RA, and area X, and increased neuronal number in the ipsilateral HVc. The T implant near RA did not produce selective growth of ipsilateral RA, HVc, or area X. Intracerebral T implants did not elevate plasma T levels, nor did they stimulate growth of two peripheral androgen sensitive targets, the syrinx and the cloacal protuberance. These results suggest that seasonal growth of the adult song circuits results from T acting directly on HVc, which then stimulates the growth of RA and area X transynaptically.

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Use of PG-21 immunocytochemistry to detect androgen receptors in the songbird brain.

Cited by 65 publications

References 26 publications

Afferent Input Is Necessary for Seasonal Growth and Maintenance of Adult Avian Song Control Circuits

Afferent Input Is Necessary for Seasonal Growth and Maintenance of Adult Avian Song Control Circuits

Seasonal-like growth and regression of the avian song control system: Neural and behavioral plasticity in adult male Gambel’s white-crowned sparrows

Act locally and think globally: Intracerebral testosterone implants induce seasonal-like growth of adult avian song control circuits

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