title: Contribution of medullary raphé to control of coughing--codeine trials in cat.
abstract: In order to determine if a codeine-sensitive control system for cough exists in the medullary raphé four microinjections of codeine (3.3 and 16.5 mM; 36.6±0.7 nl 1.5 and 3 mm rostral to the obex at the depths 1.5 and 3 mm; the total dose 1.12±0.3 nmol, 9 animals) were performed on pentobarbitone anesthetized spontaneously breathing cats. Amplitudes of abdominal muscle EMG moving averages during mechanically induced tracheobronchial cough decreased by 18% compared to control coughs (p<0.05). The duration between maxima of cough diaphragm and abdominal muscle EMG discharge, cough expiratory phase duration and period of relative motor quiescence between coughs were increased (all p<0.05). Cough number, other cough parameters, and cardiorespiratory characteristics were not altered significantly. Control microinjections of artificial cerebro-spinal fluid had no effect on coughing. Codeine sensitive neurons involved in the generation or modulation of motor pattern of tracheobronchial cough are located in the medullary midline raphé nuclei; however, their contribution to codeine induced cough suppression is limited.
authors.affiliation: Department of Medical Biophysics, Jessenius Faculty of Medicine, Comenius University, Mala Hora 4, 03601 Martin, Slovakia. poliacek@jfmed.uniba.sk
authors.forename: Ivan
authors.initials: I
authors.lastname: Poliacek
authors.forename: Michal
authors.initials: M
authors.lastname: Simera
authors.forename: Marcel
authors.initials: M
authors.lastname: Veternik
authors.forename: Peter
authors.initials: P
authors.lastname: Machac
authors.forename: Helena
authors.initials: H
authors.lastname: Barani
authors.forename: Nadezda
authors.initials: N
authors.lastname: Visnovcova
authors.forename: Erika
authors.initials: E
authors.lastname: Halasova
authors.forename: Jan
authors.initials: J
authors.lastname: Jakus
mesh_terms: D000818:Animals; D000996:Antitussive Agents / Q000008:administration & dosage*; D002415:Cats; D003061:Codeine / Q000008:administration & dosage*; D003371:Cough / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D008297:Male; D008845:Microinjections; D011903:Raphe Nuclei / Q000187:drug effects* / Q000502:physiology*; D012132:Respiratory Muscles / Q000187:drug effects / Q000502:physiology
chemical_list: D000996:Antitussive Agents; D003061:Codeine