Non-nutritive sucking in the infant can stimulate secretion of which substances in the oral mucosa via vagal innervation?

• A. Lingual lipase, gastrin, insulin and motilin
• B. Secretin and cholecystokinin
• C. Pepsin and amylase
• D. Leptin and ghrelin

Answer: (A)

Non-nutritive sucking triggers vagal (parasympathetic) stimulation that enhances secretions in the oral cavity as part of the cephalic-phase readiness for digestion. In infants, the lingual glands secrete lingual lipase directly into the saliva, and this secretion is increased by vagal input from oral-sucking activity. Lingual lipase begins fat digestion in the stomach and is especially important in newborns, who rely more on this enzyme early in life. The other substances listed are hormones produced by other parts of the GI tract or pancreas (gastrin from the stomach, motilin from the small intestine, insulin from the pancreas) and are not secreted into the oral mucosa in response to sucking. Thus, the local secretion in the oral mucosa driven by vagal innervation is lingual lipase.