Fluoxetine Affects Intestinal Motility via 5-HT3 and Muscarinic Receptors in ex vivo Mouse Model

Fluoxetine, a selective serotonin reuptake inhibitor anti-depressant, causes undesirable side effects, including diarrhea and constipation. This research investigated the direct effects of fluoxetine at 0.001, 0.01, 0.1, 1, 10, 100 µM on duodenal proximal colonic tissue contractions. The investigation aimed to determine related mechanisms using an isolated mouse intestine model. Our study showed that 0.001 μM increased amplitude contraction in but decreased tissue. application higher concentrations (1, µM) reduced contractions Moreover, we found stimulatory effect tone could be prevented by pre-incubating ondansetron atropine. findings suggest inhibition was mainly mediated via 5-HT3 receptors muscarinic signaling. These might explain conflicting gastrointestinal symptoms caused fluoxetine.