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Myocardial vagal stimulation impairs lower esophageal sphincter function
M T Caldwell1, P Marks, P J Byrne
1University Department of Surgery, St. Jame's Hospital, Dublin, Ireland.
Surgery
|November 1, 1994
Summary
Stimulating heart receptors with nicotine or friction significantly lowered lower esophageal sphincter (LES) tone in dogs. This suggests a vagal reflex may link heart conditions and gastroesophageal reflux disease.
Area of Science:
- Cardiology
- Gastroenterology
- Neurogastroenterology
Background:
- Coronary artery disease (CAD) and gastroesophageal reflux disease (GERD) often coexist.
- A direct pathophysiological link between CAD and GERD remains unestablished.
Purpose of the Study:
- To investigate the effect of myocardial vagal receptor stimulation on lower esophageal sphincter (LES) tone.
- To explore a potential vagal reflex pathway between the heart and the esophagus.
Main Methods:
- Eight adult mongrel dogs were used, with each serving as its own control.
- Myocardial vagal receptors were stimulated pharmacologically using nicotine patches applied to the epicardium.
- Mechanical stimulation of epicardial vagal receptors was performed via digital friction.
Main Results:
- Pharmacologic stimulation with nicotine caused a significant decrease in LES tone (p = 0.007).
- Mechanical stimulation also resulted in a significant reduction in LES tone (p = 0.007).
- Both stimulation methods were associated with decreased mean arterial blood pressure and heart rate.
Conclusions:
- The study suggests a direct vagal reflex pathway connecting the myocardium and the LES.
- This newly identified reflex may elucidate the high prevalence of GERD in patients with heart disease.