title: Changes in vagal afferent drive alter tracheobronchial coughing in anesthetized cats.
abstract: Unilateral cooling of the vagus nerve (<5°C, blocking mainly conductivity of myelinated fibers) and unilateral vagotomy were employed to reduce cough afferent drive in order to evaluate the effects of these interventions on the temporal features of the cough reflex. Twenty pentobarbitone anesthetized, spontaneously breathing cats were used. Cough was induced by mechanical stimulation of the tracheobronchial airways. The number of coughs during vagal cooling was significantly decreased (p<0.001). Inspiratory cough efforts were reduced by approximately 30% (p<0.001) and expiratory motor drive by more than 80% (p<0.001). Temporal analysis showed prolonged inspiratory and expiratory phases, the total cycle duration, its active portion, and the interval between maxima of the diaphragm and the abdominal activity during coughing (p<0.001). There was no significant difference in the average effects on the cough reflex between cooling of the left or the right vagus nerve. Compared to control, vagal cooling produced no significant difference in heart rate and mean arterial blood pressure (p>0.05), however, cold block of vagal conduction reduced respiratory rate (p<0.001). Unilateral vagotomy significantly reduced cough number, cough-related diaphragmatic activity, and relative values of maximum expiratory esophageal pressure (all p<0.05). Our results indicate that reduced cough afferent drive (lower responsiveness) markedly attenuates the motor drive to respiratory pump muscles during coughing and alters cough temporal features. Differences in the effects of unilateral vagal cooling and vagotomy on coughing support an inhibitory role of sensory afferents that are relatively unaffected by cooling of the vagus nerve to 5°C on mechanically induced cough.
authors.affiliation: Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia.
authors.forename: Michal
authors.initials: M
authors.lastname: Simera
authors.affiliation: Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia. Electronic address: poliacek@jfmed.uniba.sk.
authors.forename: Ivan
authors.initials: I
authors.lastname: Poliacek
authors.affiliation: Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia.
authors.forename: Marcel
authors.initials: M
authors.lastname: Veternik
authors.affiliation: Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia.
authors.forename: Lucia
authors.initials: L
authors.lastname: Babalova
authors.affiliation: Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Kotmanova
authors.affiliation: Comenius University in Bratislava, Jessenius Faculty of Medicine in Martin, Institute of Medical Biophysics, Mala Hora 4, 03601 Martin, Slovakia.
authors.forename: Jan
authors.initials: J
authors.lastname: Jakus
mesh_terms: D000344:Afferent Pathways / Q000502:physiology; D000758:Anesthesia; D000818:Animals; D002415:Cats; D003080:Cold Temperature; D003371:Cough / Q000503:physiopathology*; D005260:Female; D006993:Hypnotics and Sedatives / Q000494:pharmacology; D008297:Male; D023421:Models, Animal; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology; D010424:Pentobarbital / Q000494:pharmacology; D010812:Physical Stimulation; D012018:Reflex / Q000502:physiology*; D012119:Respiration; D012132:Respiratory Muscles / Q000502:physiology; D011984:Sensory Receptor Cells / Q000502:physiology*; D013997:Time Factors; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology*
chemical_list: D006993:Hypnotics and Sedatives; D010424:Pentobarbital
keywords: Cats; Cough afferents; Tracheobronchial cough; Unilateral vagotomy; Vagal cooling