Early life stress and hormonal status influence orexin‐1 receptor expression in structures regulating cardiorespiratory responses to CO2

Abstract Excessive cardiorespiratory responses to CO2 are a hallmark of panic disorder (PD). Female sex and exposure to early life stress are risk factors for PD. Neonatal maternal separation (NMS; 3 h/day, postnatal days 3–12) augments the ventilatory response to CO2 by ∼35% relative to controls; t...

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Main Authors: Stéphanie Fournier, Julie Plamondon, Denis Richard, Richard Kinkead
Format: Article
Language:English
Published: Wiley 2025-08-01
Series:Experimental Physiology
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Online Access:https://doi.org/10.1113/EP092431
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author Stéphanie Fournier
Julie Plamondon
Denis Richard
Richard Kinkead
author_facet Stéphanie Fournier
Julie Plamondon
Denis Richard
Richard Kinkead
author_sort Stéphanie Fournier
collection DOAJ
description Abstract Excessive cardiorespiratory responses to CO2 are a hallmark of panic disorder (PD). Female sex and exposure to early life stress are risk factors for PD. Neonatal maternal separation (NMS; 3 h/day, postnatal days 3–12) augments the ventilatory response to CO2 by ∼35% relative to controls; this effect is most notable during pro‐oestrus but is not observed in males. Orexin‐1 receptor (OX1‐R) antagonism attenuates the CO2 response of NMS females. In the limbic system, stress and ovarian hormones influence OX1‐R expression, but the impact of these factors on OX1‐Rs in regions regulating the cardiorespiratory responses to CO2 is unknown. Here, we hypothesised that ovarian hormones and NMS determine OX1‐R expression in structures regulating the CO2 response; we used in situ hybridisation to quantify OX‐1R mRNA expression in the brains of adult NMS and control rats. Brains were harvested from females that were either in pro‐oestrus (high ovarian hormones) or 2 weeks post ovariectomy (OVX; low ovarian hormones); males were included for comparison. Hormonal status influenced the intensity of the OX1‐R signal in the medial amygdala, raphe obscurus (RObs) and the A5 area, but the direction of the changes (increase vs. decrease) was structure‐specific. Significant NMS × hormonal status interactions were noted in the dorsal raphe, the locus coeruleus, the nucleus of the solitary tract and the A5 area; the effects were structure‐specific. As the dorsal raphe was the only structure in which the changes in OX1‐R expression matched the sex‐specific effect of NMS on the CO2 response, this structure likely contributes to respiratory manifestations of PD.
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spelling doaj-art-1d0e2d76e9c84e759b2f3e7e3b91742b2025-08-20T03:58:15ZengWileyExperimental Physiology0958-06701469-445X2025-08-0111081138115310.1113/EP092431Early life stress and hormonal status influence orexin‐1 receptor expression in structures regulating cardiorespiratory responses to CO2Stéphanie Fournier0Julie Plamondon1Denis Richard2Richard Kinkead3Research Center of the Québec Heart and Lung Institute Laval University Québec City Quebec CanadaResearch Center of the Québec Heart and Lung Institute Laval University Québec City Quebec CanadaResearch Center of the Québec Heart and Lung Institute Laval University Québec City Quebec CanadaResearch Center of the Québec Heart and Lung Institute Laval University Québec City Quebec CanadaAbstract Excessive cardiorespiratory responses to CO2 are a hallmark of panic disorder (PD). Female sex and exposure to early life stress are risk factors for PD. Neonatal maternal separation (NMS; 3 h/day, postnatal days 3–12) augments the ventilatory response to CO2 by ∼35% relative to controls; this effect is most notable during pro‐oestrus but is not observed in males. Orexin‐1 receptor (OX1‐R) antagonism attenuates the CO2 response of NMS females. In the limbic system, stress and ovarian hormones influence OX1‐R expression, but the impact of these factors on OX1‐Rs in regions regulating the cardiorespiratory responses to CO2 is unknown. Here, we hypothesised that ovarian hormones and NMS determine OX1‐R expression in structures regulating the CO2 response; we used in situ hybridisation to quantify OX‐1R mRNA expression in the brains of adult NMS and control rats. Brains were harvested from females that were either in pro‐oestrus (high ovarian hormones) or 2 weeks post ovariectomy (OVX; low ovarian hormones); males were included for comparison. Hormonal status influenced the intensity of the OX1‐R signal in the medial amygdala, raphe obscurus (RObs) and the A5 area, but the direction of the changes (increase vs. decrease) was structure‐specific. Significant NMS × hormonal status interactions were noted in the dorsal raphe, the locus coeruleus, the nucleus of the solitary tract and the A5 area; the effects were structure‐specific. As the dorsal raphe was the only structure in which the changes in OX1‐R expression matched the sex‐specific effect of NMS on the CO2 response, this structure likely contributes to respiratory manifestations of PD.https://doi.org/10.1113/EP092431CO2 responsecontrol of breathingorexinsex based‐differencesstress
spellingShingle Stéphanie Fournier
Julie Plamondon
Denis Richard
Richard Kinkead
Early life stress and hormonal status influence orexin‐1 receptor expression in structures regulating cardiorespiratory responses to CO2
Experimental Physiology
CO2 response
control of breathing
orexin
sex based‐differences
stress
title Early life stress and hormonal status influence orexin‐1 receptor expression in structures regulating cardiorespiratory responses to CO2
title_full Early life stress and hormonal status influence orexin‐1 receptor expression in structures regulating cardiorespiratory responses to CO2
title_fullStr Early life stress and hormonal status influence orexin‐1 receptor expression in structures regulating cardiorespiratory responses to CO2
title_full_unstemmed Early life stress and hormonal status influence orexin‐1 receptor expression in structures regulating cardiorespiratory responses to CO2
title_short Early life stress and hormonal status influence orexin‐1 receptor expression in structures regulating cardiorespiratory responses to CO2
title_sort early life stress and hormonal status influence orexin 1 receptor expression in structures regulating cardiorespiratory responses to co2
topic CO2 response
control of breathing
orexin
sex based‐differences
stress
url https://doi.org/10.1113/EP092431
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AT denisrichard earlylifestressandhormonalstatusinfluenceorexin1receptorexpressioninstructuresregulatingcardiorespiratoryresponsestoco2
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