A young patient is affected by a central nervous system infection. Which neurotransmitter is responsible for increasing gastrointestinal motility and potentially related findings?

• A. Acetylcholine
• B. Motilin
• C. Norepinephrine
• D. Serotonin

Answer: (B)

The correct answer is motilin. Motilin is a peptide hormone that plays a key role in regulating gastrointestinal motility, particularly during fasting when it helps coordinate the migrating motor complex (MMC) that is responsible for the cleansing waves of the stomach and small intestines.

In the context of a central nervous system infection, various factors can lead to changes in gastrointestinal function, and motilin levels can be affected by such illnesses. An increase in motilin can result in enhanced gastrointestinal motility, which may manifest as increased peristalsis, resulting in symptoms such as diarrhea or abdominal cramps due to the rapid movement of content through the gastrointestinal tract.

The other substances listed may have roles in the central nervous system or gastrointestinal function but do not specifically correlate with the enhancement of gastrointestinal motility in the same direct manner as motilin. Acetylcholine is important in the nervous system and can stimulate digestive processes, but is not the primary hormonal regulator like motilin. Norepinephrine generally reduces gastrointestinal motility as part of the sympathetic response. Serotonin does modulate gut movements but is not primarily responsible for the overall increase in motility associated with motilin's specific action during gastric fasting phases.