Serotonin in the gut: Blessing or a curse

Area of Science:

• Gastroenterology
• Immunology
• Endocrinology

Background:

• Serotonin (5-hydroxytryptamine or 5-HT) is predominantly synthesized and secreted in the gastrointestinal tract (95%), with a smaller fraction in the brain (5%).
• 5-HT serves as a critical enteric signaling molecule, regulating gut sensory-motor and secretory functions.

Purpose of the Study:

• To review the established and emerging roles of gut-derived serotonin (5-HT) in maintaining normal gut physiology.
• To summarize 5-HT's involvement in the pathogenesis of gut inflammation and its broader biological functions.

Main Methods:

• Literature review of accumulated and updated research on serotonin's functions in the gut and beyond.
• Synthesis of information regarding 5-HT's role in gut physiology, inflammation, immune cell activation, bone remodeling, and metabolic homeostasis.

Main Results:

• Gut-derived 5-HT is crucial for normal gut physiology and plays a significant role in immune cell activation and inflammation.
• Emerging evidence indicates 5-HT influences extra-intestinal processes, including bone remodeling and metabolic homeostasis.

Conclusions:

• Understanding the multifaceted roles of serotonin is key to differentiating its beneficial and detrimental effects.
• This knowledge may facilitate the development of novel therapeutic strategies for conditions like inflammatory bowel disease.