Abstract
The avian neuropeptide arginine vasotocin (AVT) originally characterized as the antidiuretic hormone ( Munsick et al., 1960, Endocrinol. 66, 860–871) is produced by neurosecretory cells within the brain. Numerous neuroanatomical studies that employed immunocytochemical and in situ hybridization techniques revealed such cells in the following anatomical brain locations: (a) preoptic area including supraoptic nucleus; (b) paraventricular nucleus; (c) the bed nucleus of the stria terminalis (BnST) ( Viglietti-Panzica, 1986, J. Hirnforsch. 27, 559–566; Mühlbauer et al., 1993, J. Neuroendcrinol. 5, 281–288; Jurkevich et al., 1997, Cell Tiss. Res. 287, 69–77; Aste et al., 1998, J. Comp. Neurol. 369, 141–157). The BnST which influences reproduction and sexual behavior shows sex differences in morphology, steroid responsiveness and synthesis of neuropeptides including AVT ( Viglietti-Panzica et al., 1994, Brain Res. 657, 171–184). AVT is the main endocrine regulator of fluid balance in avian species and, in addition, is involved in oviposition in these species. Our recent studies clearly demonstrated that AVT secretion after osmotic stimulation is sexually dimorphic. In order to investigate whether AVT is expressed and synthesized in the BnST in a sexually dimorphic manner we have used in situ hybridization technique and immunocytochemistry to analyze AVT gene expressing neurons in the parvocellular (small-celled nulei) BnST of adult male and female chickens. In cocks, AVT peptide-containing neurons were detected in the parvocellular BnST and the lateral septal area, whereas no AVT immunoreactive neurons were detected in the corresponding regions of the hen. Even after osmotic stimulation AVT gene expression in neurons of the parvocellular BnST of hens was not upregulated ( Jurkevich et al., 1996, Cell Tiss. Res. 287, 69–77). These results demonstrate: (a) AVT gene expression in the BnST of chickens; and (b) a strong sexual dimorphism in this region. Furthermore, AVT synthesis is regulated on the transcriptional level independent from osmotic stimuli. Thus, sex steroids might be the main regulator of AVT gene expression in the BnST. In this paper we not only review the sexual dimorphic vasotocinergic system in the BnST, we also focus on the ontogeny of sex differences and the role of gonadal hormones in organization and retention of these differences.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.