TITLE:
Cough Modulation by Upper Airway Stimuli in Cat—Potential Clinical Application?
AUTHORS:
Ivan Poliacek, Jana Plevkova, Teresa Pitts, Zuzana Kotmanova, Jan Jakus, Michal Simera
KEYWORDS:
Aspiration Reflex, Expiration Reflex, Sneeze, Swallow, Nasal Stimulation
JOURNAL NAME:
Open Journal of Molecular and Integrative Physiology,
Vol.6 No.3,
August
22,
2016
ABSTRACT: The modulation of mechanically induced tracheobronchial cough was tested by applying various
stimuli and the elicitation of other airway protective behaviors in pentobarbital anesthetized cats.
Capsaicin and histamine were injected in the nose, and mechanical nylon fiber and/or air puff
stimulation was applied to the nose and nasopharynx. Reflex responses of cough, sneeze, aspiration
reflex and expiration reflex were induced mechanically. Swallow was initiated by the injection
of water into oropharynx. Subthreshold mechanical stimulation of nasopharyngeal and nasal
mucosa, as well as water stimulation in the oropharynx and larynx, with no motor response, had
no effect on rhythmic coughing. Cough responsiveness and excitability increased with capsaicin
and air puff stimuli delivered to the nose. Vice versa, the number of cough responses was reduced
and cough latency increased when aspiration reflexes (>1) occurred before the cough stimulus or
within inter-cough intervals (passive E2 cough phase). The occurrence of swallows increased the
cough latency as well. Cough inspiratory and/or expiratory motor drive was enhanced by the
occurrence of expiration reflexes, swallows, and sneezes and also by aspiration reflex within the
inspiratory phase of cough and by nasal air puff stimuli. Complex central interactions, ordering
and sequencing of motor acts from the airways may result in the disruption of cough rhythmic
sequence but also in the enhancement of cough. Our data confirm that number of peripheral
stimuli and respiratory motor responses significantly alters cough performance. We propose
developing and testing stimulation paradigms that modify coughing and could be employed in
correcting of inappropriate or excessive coughing.