We investigated neuronal activity of the medulla oblongata
during gastroesophageal reflux-related cough (GERC). A rat
model of GERC was generated by perfusing HCl into lower
esophagus and inducing cough with citric acid. The HCl group rat
was received HCl perfusion without citric acid-induced cough.
The saline control rat was perfused with saline instead and cough
was induced. Citric acid-induced cough rat was only induced by
citric acid. Blank group rats were fed normally. Fos expressions
were observed in medulla oblongata nuclei using
immunohistochemistry. Manganese-enhanced magnetic
resonance imaging (MEMRI) was performed to detect the
Mn2+ signal following intraperitoneal injection of MnCl2. HCl
perfusion and citric acid-induced cough caused Fos expressions in
the nucleus of solitary tract (nTS), dorsal motor nucleus of the
vagus (DMV), paratrigeminal nucleus (Pa5), and intermediate
reticular nucleus (IRt), which was higher than HCl group, saline
control group, citric acid-induced cough group, and blank group.
A high Mn2+ signal was also observed in most of these nuclei in
model rats, compared with blank group animals. The Mn2+ signal
was also higher in the HCl, saline and citric acid-induced cough
group animals, compared with blank group animals. The study
showed medulla oblongata neurons were excited in a HCl
perfusion and citric acid-induced cough rat model, and nTS, DMV,
Pa5 and IRt neurons maybe involved in the cough process and
signal integrate.