Arginine vasopressin (AVP) is a neuropeptide synthesized in neurons of the mammalian brain and released via the posterior pituitary into the bloodstream where it influences the maintenance of fluid homeostasis and blood pressure. Cellular identification and distribution of AVP in the mouse hypothalamic nuclei before vision functioning has never been reported before. The distribution of AVP producing cells and their projections were examined in the hypothalamus and in the hypothalamic nuclei of the neonatal CD1 mouse using immunohistochemistry (immunoperoxidase and immunofluorescent labelling methods). Clusters of neurons labelled for AVP immunoreactivity (AVP-ir) were found in the hypothalamic nuclei as in the paraventricular (PVN), supraoptic (SON) and suprachiasmatic nuclei (SCN) of the hypothalamus. Scattered AVP producing cells were also found in the lateral hypothalamus, fornix, stria terminalis and preoptic area. Heavily stained AVP-ir fibres were found in the paraventriculo-supraoptico-neurohypophyseal tract while scattered AVP-ir fibres were found in the lateral hypothalamus and in the stria terminalis. The bed nucleus of the stria terminalis (BNST) contains more AVP-ir cells in the neonatals than in adult mice.
Key words: Arginine vasopressin, immunohistochemistry, mice, hypothalamus, suprachiasmatic nucleus, paraventricular nucleus, preoptic nucleus.
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