title: Influence of trigeminal nasal afferents on bulbar respiratory neuronal activity.
abstract: This study examined the influence of nasal trigeminal afferents, the anterior ethmoidal nerve (AEN) and posterior nasal nerves (PNN) on the spike discharges of respiratory-related neurons recorded in the ventral respiratory group (VRG) (2.6-3.5 mm lateral to the midline, from 1 mm rostral to 3 mm caudal to the obex and at depth of 2-4 mm below the dorsal surface). Electrical stimulations to the AEN and PNN were administered to 10 pentobarbital anaesthetized cats and to 8 ketamine anaesthetized, vagotomized, curarized and ventilated cats. Single shock stimulations of either nerve evoked transient and total inhibition of inspiratory activities. Expiratory-related neurons of the VRG presented three patterns of activity in response to stimulation:excitation, inhibition or inhibition followed by excitation. More generally, expiratory units are activated with a short latency. In the course of repetitive stimulation of the AEN and PNN we observed a prolongation of the spontaneous inspiratory discharge which presented transient, short inhibition in response to each shock. Most expiratory units presented a short activation which was synchronous with the transient inhibition of inspiratory activities. When repetitive stimulation provoked a sneeze-like response, we observed a progressive increase in the duration of transient inspiratory inhibition first, associated with a progressive reinforcement of transient expiratory activation. Secondarily, just before the expiratory thrust, we noted a stronger inhibition of the inspiratory activity which preceded a high-frequency (400 Hz) expiratory discharge. Nasal afferents exert a forceful excitatory effect on bulbospinal (BS) and non-bulbospinal-non-vagal (NBS-NV) expiratory cells of the VRG. The effects due to vagotomy and curarization are discussed.
authors.affiliation: CNRS URA 1331, UFR de médecine, Amiens France.
authors.forename: F
authors.initials: F
authors.lastname: Wallois
authors.forename: J M
authors.initials: JM
authors.lastname: Macron
authors.forename: V
authors.initials: V
authors.lastname: Jounieaux
authors.forename: B
authors.initials: B
authors.lastname: Duron
mesh_terms: D000200:Action Potentials; D000344:Afferent Pathways / Q000502:physiology*; D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D005260:Female; D001239:Inhalation / Q000187:drug effects; D007649:Ketamine / Q000494:pharmacology; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009666:Nose / Q000294:innervation*; D009830:Olfactory Bulb / Q000502:physiology*; D010424:Pentobarbital / Q000494:pharmacology; D010791:Phrenic Nerve / Q000187:drug effects / Q000502:physiology; D012119:Respiration / Q000187:drug effects / Q000502:physiology*; D014276:Trigeminal Nerve / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology
chemical_list: D007649:Ketamine; D010424:Pentobarbital