ABSTRACT
Aims: Our aim was to measure the myoelectric modifications during gastric acid secretion along with the gastric pH in a rat model and to detect the gastrointestinal (GI) myoelectric changes in adolescents suffering from gastroesophageal reflux disease (GERD) along with the esophageal pH measurement. Main methods: In anesthetized rats, gastric acid secretion was initiated with intragastric histamine (50 mg/kg), and gastric pH, GI myoelectric activity and mechanical GI contractions were measured with intragastric pH electrode, subcutaneously implanted smooth muscle electromyography (SMEMG) electrodes and organ implanted strain gauges, respectively. In the clinical study, esophageal pH and GI myoelectric activity were measured in adolescents suffering from GERD with intraesophageal pH electrode and SMEMG electrodes placed on the abdominal surface, respectively. The SMEMG records were analyzed by fast Fourier transformation (FFT) and power spectrum density maximum (PsDmax) values were calculated for the GI segments. Key findings: In rats, histamine initiated an immediate increase in gastric PsDmax, which preceded the significant reduction in gastric pH by 75 min. The myoelectric change was independent of mechanical GI contractions. In adolescents, the GERD episodes were preceded by a significant increase in gastric PsDmax 45 min earlier. These changes were independent of motion or meals. Significance: Increased gastric myoelectric activity during histamine stimulation or GERD might be linked to the enhanced activity of the gastric proton pump, indicating a link between gastric acid secretion and GERD episodes. It is supposed that SMEMG might be a tool for predicting forthcoming reflux episodes in GERD.
ABSTRACT
AIMS: Non-invasive and simultaneous recording of gastrointestinal (GI) activity during stress induction is still an unexplored field. In our previous investigation, the stress-induced alteration of the gastrointestinal tract was explored in rats. Our aims were to expand our previous rat experiment and to induce stress response in rats (Study 1) and humans (Study 2) to detect the GI tract activity, heart rate and body temperature. MATERIALS AND METHODS: In the preclinical sample, acute stress was induced by immobilization in Sprague-Dawley rats (N = 10). Acute stress response was generated by the Trier Social Stress Test among healthy volunteers (N = 16). Detection of acute stress was measured by using smooth muscle electromyography, which recorded the myoelectric waves of the gastrointestinal tract (stomach, ileum and colon) simultaneously with heart rate and body temperature in rats and humans. KEY FINDINGS: The myoelectric waves of the stomach, the cecum and the ileum increased during immobilization in rats, rising in parallel with heart rate and the dermal temperature of the abdominal surface. The same alterations were found during the stress period among humans, except in the case of the colon, where no change was detected. SIGNIFICANCE: The crucial role of the GI tract in stress response was revealed by translating the outcome of basic research into human results. The similar GI alterations during stress in rats and humans underpin the robustness of our findings. In summary, our preliminary translational-based study can serve as an appropriate basis for further human studies.
