title: Hypothalamic orexin's role in exacerbated cutaneous vasodilation responses to an anxiogenic stimulus in a surgical menopause model.
abstract: Distressing symptoms such as hot flashes and sleep disturbances affect over 70% of women approaching menopause for an average of 4-7 years, and recent large cohort studies have shown that anxiety and stress are strongly associated with more severe and persistent hot flashes and can induce hot flashes. Although high estrogen doses alleviate symptoms, extended use increases health risks, and current non-hormonal therapies are marginally better than placebo. The lack of effective non-hormonal treatments is largely due to the limited understanding of the mechanisms that underlie menopausal symptoms. One mechanistic pathway that has not been explored is the wake-promoting orexin neuropeptide system. Orexin is exclusively synthesized in the estrogen receptor rich perifornical hypothalamic region, and has an emerging role in anxiety and thermoregulation. In female rodents, estrogens tonically inhibit expression of orexin, and estrogen replacement normalizes severely elevated central orexin levels in postmenopausal women. Using an ovariectomy menopause model, we demonstrated that an anxiogenic compound elicited exacerbated hot flash-associated increases in tail skin temperature (TST, that is blocked with estrogen), and cellular responses in orexin neurons and efferent targets. Furthermore, systemic administration of centrally active, selective orexin 1 or 2 and dual receptor antagonists attenuated or blocked TST responses, respectively. This included the reformulated Suvorexant, which was recently FDA-approved for treating insomnia. Collectively, our data support the hypothesis that dramatic loss of estrogen tone during menopausal states leads to a hyperactive orexin system that contributes to symptoms such as anxiety, insomnia, and more severe hot flashes. Additionally, orexin receptor antagonists may represent a novel non-hormonal therapy for treating menopausal symptoms, with minimal side effects.
authors.affiliation: Department of Anatomy & Cell Biology, USA; Paul and Carole Stark Neurosciences Research Institute, USA; Program in Medical Neurosciences, Paul and Carole Stark Neurosciences Research Institute, USA.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Federici
authors.affiliation: Department of Anatomy & Cell Biology, USA; Paul and Carole Stark Neurosciences Research Institute, USA.
authors.forename: Izabela Facco
authors.initials: IF
authors.lastname: Caliman
authors.affiliation: Paul and Carole Stark Neurosciences Research Institute, USA; Department of Psychiatry; Indiana University School of Medicine, USA.
authors.forename: Andrei I
authors.initials: AI
authors.lastname: Molosh
authors.affiliation: Department of Anatomy & Cell Biology, USA.
authors.forename: Stephanie D
authors.initials: SD
authors.lastname: Fitz
authors.affiliation: Department of Anatomy & Cell Biology, USA; Paul and Carole Stark Neurosciences Research Institute, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Truitt
authors.affiliation: Janssen Research and Development LLC, USA.
authors.forename: Pascal
authors.initials: P
authors.lastname: Bonaventure
authors.affiliation: Science of Nursing Care Department, Indiana University School of Nursing, Indianapolis, IN 46202, USA.
authors.forename: Janet S
authors.initials: JS
authors.lastname: Carpenter
authors.affiliation: Paul and Carole Stark Neurosciences Research Institute, USA; Department of Psychiatry; Indiana University School of Medicine, USA.
authors.forename: Anantha
authors.initials: A
authors.lastname: Shekhar
authors.affiliation: Department of Anatomy & Cell Biology, USA; Paul and Carole Stark Neurosciences Research Institute, USA. Electronic address: philjohn@iupui.edu.
authors.forename: Philip L
authors.initials: PL
authors.lastname: Johnson
mesh_terms: D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001833:Body Temperature Regulation / Q000187:drug effects* / Q000502:physiology*; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D007031:Hypothalamus / Q000187:drug effects; D008593:Menopause / Q000187:drug effects* / Q000502:physiology; D023421:Models, Animal; D009474:Neurons / Q000187:drug effects; D000068796:Orexin Receptor Antagonists / Q000494:pharmacology; D000068797:Orexins / Q000502:physiology*; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000187:drug effects
chemical_list: D014151:Anti-Anxiety Agents; D004967:Estrogens; D000068796:Orexin Receptor Antagonists; D000068797:Orexins
keywords: Cutaneous; Estrogen; Hot flash; Hypocretin; Hypothalamus; Menopause; Norepinephrine; Orexin; Serotonin; Thermoregulation