title: Long-lasting bradypnea induced by repeated social defeat.
abstract: Repeated social defeat in the rat induces long-lasting cardiovascular changes associated with anxiety. In this study, we investigated the effects of repeated social defeat on breathing. Respiratory rate was extracted from the respiratory sinus arrhythmia (RSA) peak frequency of the ECG in rats subjected to social defeat for 4 consecutive days. Respiratory rate was recorded under anesthesia 6 days (D+10) or 26 days (D+30) after social defeat. At D+10, defeated (D) rats spent less time in the open arms of the elevated plus maze test, had heavier adrenal glands, and displayed bradypnea, unlike nondefeated animals. At D+30, all signs of anxiety had disappeared. However, one-half of the rats still displayed bradypnea (DL rats, for low respiratory rate indicated by a lower RSA frequency), whereas those with higher respiratory rate (DH rats) had recovered. Acute blockade of the dorsomedial hypothalamus (DMH) or nucleus tractus solitarii (NTS) 5-HT3 receptors reversed bradypnea in all D rats at D+10 and in DL rats at D+30. Respiratory rate was also recorded in conscious animals implanted with radiotelemetric ECG probes. DH rats recovered between D+10 and D+18, whereas DL rats remained bradypneic until D+30. In conclusion, social stress induces sustained chronic bradypnea mediated by DMH neurons and NTS 5-HT3 receptors. These changes are associated with an anxiety-like state that persists until D+10, followed by recovery. However, bradypnea may persist in one-half of the population up until D+30, despite apparent recovery of the anxiety-like state.
authors.affiliation: Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Institut National de la Santé et de la Recherche Médicale, UMR-S 975, Centre National de la Recherche Scientifique, UMR 7225, Faculté de Médecine University Pierre and Marie Curie, Site Pitié-Salpêtrière, Paris, France; Sorbonne Universités, University Pierre and Marie Curie University Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France;
authors.forename: Charly
authors.initials: C
authors.lastname: Brouillard
authors.affiliation: Blood Pressure, Brain and Behavior Laboratory, School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia.
authors.forename: Pascal
authors.initials: P
authors.lastname: Carrive
authors.affiliation: Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Institut National de la Santé et de la Recherche Médicale, UMR-S 975, Centre National de la Recherche Scientifique, UMR 7225, Faculté de Médecine University Pierre and Marie Curie, Site Pitié-Salpêtrière, Paris, France;
authors.forename: Françoise
authors.initials: F
authors.lastname: Camus
authors.affiliation: Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Institut National de la Santé et de la Recherche Médicale, UMR-S 975, Centre National de la Recherche Scientifique, UMR 7225, Faculté de Médecine University Pierre and Marie Curie, Site Pitié-Salpêtrière, Paris, France;
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Bénoliel
authors.affiliation: Sorbonne Universités, University Pierre and Marie Curie University Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France; Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Charles Foix, Service de Pneumologie et Réanimation Médicale, Paris, France; and.
authors.forename: Thomas
authors.initials: T
authors.lastname: Similowski
authors.affiliation: Centre de Recherche de l'Institut du Cerveau et de la Moelle Epinière, Institut National de la Santé et de la Recherche Médicale, UMR-S 975, Centre National de la Recherche Scientifique, UMR 7225, Faculté de Médecine University Pierre and Marie Curie, Site Pitié-Salpêtrière, Paris, France; Sorbonne Universités, University Pierre and Marie Curie University Paris 06, Institut National de la Santé et de la Recherche Médicale, UMRS1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France; caroline.sevoz-couche@upmc.fr.
authors.forename: Caroline
authors.identifier: 0000-0003-2868-9279
authors.initials: C
authors.lastname: Sévoz-Couche
mesh_terms: D000818:Animals; D001007:Anxiety / Q000503:physiopathology*; D001522:Behavior, Animal; D007040:Hypoventilation / Q000503:physiopathology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D056152:Respiratory Rate; D012919:Social Behavior; D013315:Stress, Psychological
keywords: anxiety; breathing; serotonin; social defeat; telemetric recording