Article (Scientific journals)
The parvocellular vasotocin system of Japanese quail: A developmental and adult model for the study of influences of gonadal hormones on sexually differentiated and behaviorally relevant neural circuits
Panzica, G. C.; Balthazart, Jacques; Pessatti, M. et al.
2002In Environmental Health Perspectives, 110 (Suppl. 3), p. 423-428
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Keywords :
avian brain; copulatory behavior; development; sexual dimorphism; vasotocin
Abstract :
[en] Vasotocin (VT; the antidiuretic hormone of birds) is synthesized by diencephalic magnocellular neurons projecting to the neurohypophysis. A sexually dimorphic system of VT-immunoreactive (ir) parvocellular elements has been described within the male medial preoptic nucleus (POM) and the nucleus of the stria terminalis, pars medialis (BSTm). VT-ir fibers are present in many diencephalic and extradiencephalic locations, and quantitative morphometric analyses demonstrated their sexually dimorphic distribution in regions involved in the control of different aspects of reproduction. Moreover, systemic or intracerebroventricular injections of VT markedly inhibit the expression of some aspects of male sexual behavior. In adult animals, circulating levels of testosterone (T) have a profound influence on the VT immunoreactivity within BSTm, POM, and lateral septum. Castration markedly decreases the immunoreaction, whereas T-replacement therapy restores a situation similar to the intact birds. We observed no changes in gonadectomized females treated with T. These changes parallel similar changes in male copulatory behavior (not present in castrated male quail, fully expressed in castrated, T-treated males). The restoration by T of the VT immunoreactivity in castrated male quail could be fully mimicked by a treatment with estradiol (E-2), suggesting that the aromatization of T into E-2 may play a key limiting role in both the activation of male sexual behavior and the induction of VT synthesis. This dimorphism has an organizational nature: administration of E-2 to quail embryos (a treatment that abolishes male sexual behavior) results in a dramatic decrease of the VT immuno reactivity in sexually dimorphic regions. Conversely, the inhibition of E-2 synthesis during embryonic life (a treatment that stimulates the expression of male copulatory behavior in treated females exposed in adulthood to T) results in a malelike distribution of VT immunoreactivity. The VT parvocellular system of the Japanese quail can therefore be considered an accurate marker of the sexual differentiation of brain circuits mediating copulatory behavior and could be a very sensitive indicator of the activity of estrogenlike substances on neural circuits.
Disciplines :
Public health, health care sciences & services
Neurosciences & behavior
Environmental sciences & ecology
Author, co-author :
Panzica, G. C.
Balthazart, Jacques  ;  Université de Liège - ULiège > Département des sciences biomédicales et précliniques > Biologie de la différenciation sexuelle du cerveau
Pessatti, M.
Viglietti-Panzica, C.
Language :
English
Title :
The parvocellular vasotocin system of Japanese quail: A developmental and adult model for the study of influences of gonadal hormones on sexually differentiated and behaviorally relevant neural circuits
Publication date :
June 2002
Journal title :
Environmental Health Perspectives
ISSN :
0091-6765
Publisher :
Us Dept Health Human Sciences Public Health Science, Res Triangle Pk, United States - North Carolina
Volume :
110
Issue :
Suppl. 3
Pages :
423-428
Peer reviewed :
Peer Reviewed verified by ORBi
Available on ORBi :
since 21 April 2009

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