Distribution and regulation of telencephalic aromatase expression in the zebra finch revealed with a specific antibody

Saldanha, Colin J.; Tuerk, Melanie J; Kim, Yong Hwan; Fernandes, Augustine; Arnold, Arthur P.; Schlinger, Barney A.

doi:10.1002/1096-9861(20000807)423:4<619::aid-cne7>3.0.co;2-u

Cited by 236 publications

(328 citation statements)

References 38 publications

Supporting

Mentioning

298

Contrasting

Unclassified

Order By: Relevance

“…Since tritiated substrates are acted upon by both 3β-HSD and aromatase in these slices, it falls to reason that either the same cells express both the enzymes and co-factors or that the enzymes are present in separate cells that are spatially co-localized within the slice. Whereas the distribution of aromatase-expressing cells is well characterized in the zebra finch (Saldanha et al, 2000) additional experiments are required to ascertain the precise cellular localization of 3β-HSD in the songbird brain. Importantly, these conversions occurred in two regions with implications for the development and function of neural structures controlling song: the lateral ventricle with its associated proliferative zone and the areas containing both RA and HVC.…”

Section: Discussionmentioning

confidence: 99%

Activities of 3β-HSD and aromatase in slices of developing and adult zebra finch brain

Tam¹,

Schlinger²

2007

General and Comparative Endocrinology

Self Cite

View full text Add to dashboard Cite

Sex steroids influence the development and function of the songbird brain. Developmentally, the neural circuitry underlying song undergoes masculine differentiation under the influence of estradiol. In adults, estradiol stimulates song behavior and the seasonal growth of song control circuits. There is good reason to believe that these neuroactive estrogens are synthesized in the brain. At all ages, estrogens could act at the lateral ventricle, during migration, or where song nuclei exist or will form. We investigated the activity of two critical steroidogenic enzymes, 3β-hydroxysteroid dehydrogenase/isomerase (3βHSD) and aromatase, using a slice culture system. Sagittal brain slices were collected from juvenile (posthatch day 20) and adult zebra finches containing either the lateral ventricle, where neurons are born, or the telencephalic song nuclei HVC and RA. The slices were incubated with 3 H dehydroepiandrosterone or 3 H-androstenedione. Activity was determined by isolating certain products of 3βHSD (5α-androstanedione, 5β-androstanedione, estrone, and estradiol) and aromatase (estrone and estradiol). Activities of both 3βHSD and aromatase were detected in all slices and were confirmed using specific enzyme inhibitors. We found no significant difference in activity between adult males and females in either region for either enzyme. Juvenile female slices containing the lateral ventricle, however, showed greater levels of 3βHSD activity than did similar slices from age-matched males. Determination of the activity of these critical steroidogenic enzymes in slice culture has implications for the role of neurosteroids in brain development.

show abstract

Section: Discussionmentioning

confidence: 99%

Activities of 3β-HSD and aromatase in slices of developing and adult zebra finch brain

Tam¹,

Schlinger²

2007

General and Comparative Endocrinology

Self Cite

View full text Add to dashboard Cite

show abstract

“…These neuronal groups are mainly located in the hypothalamic/preoptic (medial preoptic nucleus, ventromedial nucleus) and limbic system (bed nucleus of stria terminalis, amygdala, hippocampus, septum, etc), but more scattered populations of aromatase expressing neurons are also present in the cerebral cortex [24,160,215,216,252,271]. In zebra finches and canaries, aromatase is also detected in high concentrations in parts of the nidopallium adjacent to the song control nucleus HVC [14,166,222]. In contrast, in the brain of teleost fishes, aromatase is expressed in radial glia [93].…”

Section: The Fast Effects Of Estrogens: Systemic or Central Origin Ofmentioning

confidence: 99%

Functional significance of the rapid regulation of brain estrogen action: Where do the estrogens come from?

2006

View full text Add to dashboard Cite

Estrogens exert a wide variety of actions on reproductive and non-reproductive functions. These effects are mediated by slow and long lasting genomic as well as rapid and transient non-genomic mechanisms. Besides the host of studies demonstrating the role of genomic actions at the physiological and behavioral level, mounting evidence highlights the functional significance of non-genomic effects. However, the source of the rapid changes in estrogen availability that are necessary to sustain their fast actions is rarely questioned. For example, the rise of plasma estrogens at pro-estrus that represents one of the fastest documented changes in plasma estrogen concentration appears too slow to explain these actions. Alternatively, estrogen can be synthesized in the brain by the enzyme aromatase providing a source of locally high concentrations of the steroid. Furthermore, recent studies demonstrate that brain aromatase can be rapidly modulated by afferent inputs, including glutamatergic afferents. A role for rapid changes in estrogen production in the central nervous system is supported by experiments showing that acute aromatase inhibition affects nociception as well as male sexual behavior and that preoptic aromatase activity is rapidly (within min) modulated following mating. Such mechanisms thus fulfill the gap existing between the fast actions of estrogen and their mode of production and open new avenues for the understanding of estrogenic effects on the brain.

show abstract

“…Indeed, nT has an important fiber projection to the POM (Panzica et al, 1996;Thompson et al, 1998), where we found an increased ER expression during the nonbreeding season. Thus, the E2 formed in nT may act transynaptically on other nuclei such as the POM, which is involved in the regulation of song behavior Riters and Ball, 1999;Saldanha et al, 2000;Riters and Alger, 2004). The strong tendency for increased AROM expression in nT in male spotted antbirds occurred during the nonbreeding season when they have low plasma levels of T. This is in contrast with results on temperate birds in which AROM expression (and/or activity) was increased by T-treatment (Fusani et al, 2001) or positively correlated with territorial behavior (Soma et al, 1999a(Soma et al, , 2003.…”

Section: Ar and Arom Expression In Ntmentioning

confidence: 99%

Low sex steroids, high steroid receptors: Increasing the sensitivity of the nonreproductive brain

Canoine

Fusani

Schlinger

et al. 2006

Developmental Neurobiology

View full text Add to dashboard Cite

Male aggressive behavior is generally regulated by testosterone (T). In most temperate breeding males, aggressive behavior is only expressed during the reproductive period. At this time circulating T concentrations, brain steroid receptors, and steroid metabolic enzymes are elevated in many species relative to the nonreproductive period. Many tropical birds, however, display aggressive behavior both during the breeding and the nonbreeding season, but plasma levels of T can remain low throughout the year and show little seasonal fluctuation. Studies on the year-round territorial spotted antbird (Hylophylax n. naevioides) suggest that T nevertheless regulates aggressive behavior in both the breeding and nonbreeding season. We hypothesize that to regulate aggressive behaviors during the nonbreeding season, when T is at its minimum, male spotted antbirds increase brain sensitivity to steroids. This can be achieved by locally up-regulating androgen receptors (ARs), estrogen receptors (ERs), or the enzyme aromatase (AROM) that converts T into estradiol. We therefore compared mRNA expression of AR, ERa, and AROM in freeliving male spotted antbirds across reproductive and nonreproductive seasons in two brain regions known to regulate both reproductive and aggressive behaviors. mRNA expression of ER in the preoptic area and AR in the nucleus taeniae were elevated in male spotted antbirds during the nonbreeding season when circulating T concentrations were low. This unusual seasonal receptor regulation may represent a means for the year-round regulation of vertebrate aggressive behavior via steroids by increasing the brain's sensitivity to sex steroids during the nonbreeding season.

show abstract

Distribution and regulation of telencephalic aromatase expression in the zebra finch revealed with a specific antibody

Cited by 236 publications

References 38 publications

Activities of 3β-HSD and aromatase in slices of developing and adult zebra finch brain

Activities of 3β-HSD and aromatase in slices of developing and adult zebra finch brain

Functional significance of the rapid regulation of brain estrogen action: Where do the estrogens come from?

Low sex steroids, high steroid receptors: Increasing the sensitivity of the nonreproductive brain

Contact Info

Product

Resources

About