However, others concluded that the esophagoprotective activity of melatonin against GERD might be related to the inhibitory effect of this indole on gastric acid secretion and due to stimulation of gastrin release, which might attenuate the gastro-esophageal reflux by stimulation of the contractile activity of the lower esophageal sphincter [29]. This evidence concerns the gene GAST and gastroesophageal reflux disease.