title: Respiratory chemoreflex response inhibition by dorsomedian hypothalamic nucleus activation in rats.
abstract: Recent observations from our group seem to indicate that repeated stress-evoked dorsomedian hypothalamic nucleus (DMH) activation in rats can lead to persistent bradypnea. One possibility was that respiratory responses to peripheral chemoreceptor activation were reduced by DMH stimulation. In the present study, we therefore investigated the effect of minimal supra-threshold DMH stimulation on respiratory carotid chemoreflex responses. For this purpose, the chemoreflex was activated by potassium cyanide (KCN, 40μg/rat, i.v.) during electrical and chemical stimulation of the DMH. In both situations, changes in breathing frequency but not tidal volume responses to KCN administration were reduced. These findings suggest that low DMH neurotransmission negatively affects respiratory chemoreflex responses and may be involved in stress-induced bradypnea.
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMR_S 1158, Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005, Paris, France; APHP, Groupe Hospitalier Pitié-Salpêtrière, Charles Foix, Service de Pneumologie et Réanimation Médicale (Département R3J), 75013 Paris, France.
authors.forename: Tabinda
authors.initials: T
authors.lastname: Zafar
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMR_S 1158, Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005, Paris, France; APHP, Groupe Hospitalier Pitié-Salpêtrière, Charles Foix, Service de Pneumologie et Réanimation Médicale (Département R3J), 75013 Paris, France.
authors.forename: Charly
authors.initials: C
authors.lastname: Brouillard
authors.affiliation: Sorbonne Universités, UPMC Univ Paris 06, INSERM, UMR_S 1158, Neurophysiologie Respiratoire Expérimentale et Clinique, F-75005, Paris, France; APHP, Groupe Hospitalier Pitié-Salpêtrière, Charles Foix, Service de Pneumologie et Réanimation Médicale (Département R3J), 75013 Paris, France. Electronic address: caroline.sevoz-couche@upmc.fr.
authors.forename: Caroline
authors.initials: C
authors.lastname: Sévoz-Couche
mesh_terms: D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002628:Chemoreceptor Cells / Q000502:physiology*; D004302:Dorsomedial Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D004558:Electric Stimulation; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D008297:Male; D008845:Microinjections; D011190:Potassium Cyanide; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000502:physiology*; D012119:Respiration; D059246:Tachypnea / Q000503:physiopathology; D013990:Tidal Volume
chemical_list: D058787:GABA-A Receptor Antagonists; D011190:Potassium Cyanide; D001640:Bicuculline
keywords: Bicuculline; Carotid chemoreflex; Hypothalamus; KCN; Respiratory responses