Keywords: کمترین اختلاف فشار; Stomach; Gastric Barostat; Gastric Accommodation; Gastric Emptying; Clinical Trial; Drug; DSS; dyspepsia symptom severity; EPS; epigastric pain syndrome; FD; functional dyspepsia; HADS; Hospital Anxiety Depression Scale; 5-HT; 5-hydroxytryptamine; MDP; mi