Acute hypernatremia promotes anxiolysis and attenuates stress-induced activation of the hypothalamic-pituitary-adrenal axis in male mice

作者：Smith Justin A; Wang Lei; Hiller Helmut; Taylor Christopher T; de Kloet Annette D; Krause Eric G^*

来源：Physiology & Behavior, 2014, 136: 91-96.

DOI：10.1016/j.physbeh.2014.03.027

• Oxytocin
• Corticotropin-releasing-hormone
• Anxiety
• Depression
• Hypertension
• Hypernatremia

Previous investigation by our laboratory found that acute hypernatremia potentiates an oxytocinergic tone that inhibits parvocellular neurosecretory neurons in the paraventricular nucleus of the hypothalamus (PVN), attenuates restraint-induced surges in corticosterone (CORT), and reduces anxiety-like behavior in male rats. To investigate the neural mechanisms mediating these effects and extend our findings to a more versatile species, we repeated our studies using laboratory mice. In response to 2.0 M NaCl injections, mice had increased plasma sodium concentrations which were associated with a blunted rise in CORT subsequent to restraint challenge relative to 0.15 M NaCl injected controls. Immunofluorescent identification of the immediate early gene product Fos found that 2.0 M NaCl treatment increased the number of activated neurons producing oxytocin in the PVN. To evaluate the effect of acute hypernatremia on PVN neurons producing corticotropin-releasing hormone (CRH), we used the Cre-lox system to generate mice that produced the red fluorescent protein, tdTomato, in cells that had Cre-recombinase activity driven by CRH gene expression. Analysis of brain tissue from these CRH-reporter mice revealed that 2.0 M NaCl treatment caused a dramatic reduction in Fos-positive nuclei specifically in CRH-producing PVN neurons. This altered pattern of activity was predictive of alleviated anxiety-like behavior as mice administered 2.0 M NaCl spent more time exploring the open arms of an elevated-plus maze than 0.15 M NaCl treated controls. Taken together, these results further implicate an oxytocin-dependent inhibition of CRH neurons in the PVN and demonstrate the impact that slight elevations in plasma sodium have on hypothalamic-pituitary-adrenocortical axis output and anxiety-like behavior.

• 出版日期2014-9