PT  - JOURNAL ARTICLE
AU  - Chayra Abdou
AU  - Sissi On
AU  - Bruno Demoulin
AU  - Odile Ruckebusch
AU  - Anne-Laure Leblanc
AU  - Noelle Bertin
AU  - François Marchal
AU  - Silvia Varechova
TI  - Slowly adapting strtech receptors upregulate mixed cough responses in the rabbit
DP  - 2012 Sep 01
TA  - European Respiratory Journal
PG  - P3787
VI  - 40
IP  - Suppl 56
4099  - http://erj.ersjournals.com/content/40/Suppl_56/P3787.short
4100  - http://erj.ersjournals.com/content/40/Suppl_56/P3787.full
SO  - Eur Respir J2012 Sep 01; 40
AB  - Rationale. Inhibition of slowly adapting stretch receptors (SARS) inhibits the cough reflex (CR), but it is not clear whether SARS stimulation facilitates CR and/or expiration reflex (ER). The issue is relevant to the long term understanding of chronic cough because those mechanisms that regulate cough are poorly understood.The aim of the study was to demonstrate whether SARS stimulation by continuous positive airway pressure (CPAP) alters CR and/or ER in the rabbit.Methods: 5 rabbits were anesthetized and tracheostomized. The trachea was exoposed to punctuate mechanical stimuli at control and with 4-5 hPa CPAP. 24 stimulations were aimed in each condition in each animal. CR and ER were identified from airflow and volume signals, diaphragmatic and abdominal muscle electrical activity. The reflexes were defined as a forced expiratory effort preceded (CR) or not (ER) by an augmented inspiration. Mixed responses were differentiated from the pattern of the first breath as ER/CR and CR/ER.Results: 241 stimulations, evenly distributed in inspiration and expiration, were obtained at control (n = 121) and on CPAP (n = 120). The overall incidence of positive responses significantly increased from 66% at control to 85% on CPAP (p = 0.0005). Incidence of ER, CR or CR/ER was not significantly altered. In contrast the mixed ER/CR response significantly increased from 14% at control to 38% on CPAP (p = 0.0005).Conclusions. SARS stimulation up regulates airway defensive reflexes, namely ER/CR. Thus SARS appear to sensitize preferentially those ER-facilitated coughs. It is speculated that a proper identification of airway defensive responses in patients may be relevant to a better understanding of chronic cough.