Vasopressinergic Regulation of the Hypothalamic Pituitary Adrenal Axis and Stress Adaptation

“…leading to the production of intermediate early genes or transcription factors capable to interact with glucocorticoid receptors and to modify their activity at the responsive element in the gene promoter (Diamond et al., 1990; Morgan and Curran, 1991; Webster and Cidlowski, 1999).”

“Glucocorticoids are likely to act at multiple sites, inhibiting VP secretion by direct actions on the parvocellular neuron, and indirectly by modifying the activity of neural pathways to the parvocellular neuron such as GABAergic and glutamatergic afferents (Herman and Cullinan, 1997; Kiss, 1998).”

“Upstream ORFs have been described in yeast and several eukaryotic mRNAs and are recognized to reduce the ability of ribosomes to linearly scan the V1b 50UTR mRNA according to conventional scanning models and therefore to slow translation (Kozak, 1991).”

“…leading to the production of intermediate early genes or transcription factors capable to interact with glucocorticoid receptors and to modify their activity at the responsive element in the gene promoter (Diamond et al., 1990; Morgan and Curran, 1991; Webster and Cidlowski, 1999).”

“In humans and rodents, VP alone is a weak stimulus of ACTH secretion, but through its interaction with CRH it contributes to maintaining corticotroph responsiveness in spite of elevated glucocorticoid levels during chronic stress (Gilles et al., 1982; Antoni, 1993; Aguilera, 1994).”

“Recent studies show that glucocorticoids induce the release of endogenous cannabinoids in the PVN, which can mediate rapid indirect, non-genomic glucocorticoid feedback in the parvocellular neuron (Di et al., 2003).”

“Circulating glucocorticoids exert a negative feedback effect on the expression of CRH and VP in parvocellular PVN neurons (Dallman et al., 1987), but there is evidence of preferential inhibition of VP compared with CRH expression (Ma et al.”

“external zone of the median eminence (Antoni, 1993).”

“Also, VP markedly potentiates the stimulatory effects of corticotropin releasing hormone (CRH) on ACTH secretion (Gilles et al., 1982; DeGoeij et al., 1991; Aguilera, 1994).”

“In addition to receptor synthesis, the number of active VP receptors could be influenced by ligand binding, leading to receptor desensitization and internalization as occurs with other G-protein coupled receptors (Catt et al., 1979; Ferguson and Caron, 1998).”

“As such, VP is part of the hypothalamic-pituitaryadrenal (HPA) axis, a system involved in the neuroendocrine stress response (Herman, 1995; Volpi et al., 2004).”

“Although the role of vasopressin in regulating ACTH secretion in responses to stress is well known (Volpi et al., 2004), current evidence suggests that vasopressin does not regulate basal HPA axis activity.”

“…the role of the Avpr1b in regulating adrenocorticotropin hormone from the anterior pituitary in response to stress, especially chronic, has been extensively studied (for reviews, see (Engelmann et al., 2004; Volpi et al., 2004)) ever since the receptor was first described (Antoni et al., 1984).”