Cough reflex in rabbits 24-h and 48-h after sulphur dioxide breathing

The cough reflex elicitability (CRE), cough reflex strength (CRS) and Hering-Breuer inflation reflex (HBIR) were studied in 51 anaesthetized (Pentobarbital Spofa, 30 mg/kg, i.v.) female rabbits 24-h and 48-h after SO2 breathing. To provoke cough, the interior of the trachea and carina were stroked with a polyethylene catheter. To elicit the HBIR, the lungs were inflated to 1.0 kPa intratracheal pressure. Intrapleural and systemic blood pressures were recorded. The CRE, CRS and HBIR obtained 24-h and 48-h after SO2 breathing were compared with correspondent values of control animals. It was found, that CRE and HBIR were fully recovered 24-h after SO2 breathing, but the CRS was still decreased, however, there were no significant differences in CRE, CRS and HBIR between animals 48-h after SO2 breathing and control animals. It can be concluded, that decrease of the CRS 24-h after SO2 breathing is not due to slowly adapting stretch receptors block of airways.