Enterochromaffin cells

Enterochromaffin (EC) cells are specialized enteroendocrine cells scattered throughout the lining of the small intestine and colon. They act as the gut’s sensory sentinels, translating chemical and mechanical signals from food and microbes into physiological responses. Their hallmark function is the synthesis and release of serotonin (5-hydroxytryptamine, 5-HT), a powerful neurotransmitter that regulates gut motility, secretion, and communication with the nervous system. In fact, about 90% of the body’s serotonin originates from EC cells, linking the gut to mood, pain, and behavior through the gut–brain axis. Beyond serotonin, EC cells also express mechanosensitive ion channels (Piezo2) and chemosensory receptors, allowing them to respond to stretch, nutrients, and microbial metabolites. Disruption of EC cell function has been implicated in irritable bowel syndrome, inflammatory bowel disease, and mood disorders, underscoring their dual role in gastrointestinal and neurological health.