Milena Saqui, Ph.D., Research Fellow, Internal Medicine (Merchant laboratory)
This is an image of mouse colon, stained with markers of cell membranes (b-catenin, red) and cell nuclei (blue). The green cell is an enteroendocrine cell (EC) that produces serotonin. EC are scattered throughout the intestine and colon. During acute injury, or bacterial or viral infection (for example in the case of food poisoning), the serotonin secreted by EC induces muscle contraction and fluid secretion. This results in increased gut motility (producing crampy abdominal pain) and generates diarrhea, both of which help to expel the infectious agents or toxins from the GI tract.