Cellular and Molecular Neurobiology
Author: Paulina Orúe | Email: porue@uade.edu.ar
Paulina Orúe1°2°, Azul Galo2°3°, Mauro Marchetto2°, Maximiliano Katz2°3°4°
1° Universidad Argentina de la Empresa. Facultad de Ingeniería
2° CONICET – Universidad de Buenos Aires. Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay). Buenos Aires, Argentina
3° Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Buenos Aires, Argentina
4° Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)
Serotonin (5-HT) is a key neurotransmitter involved in mood regulation, appetite, sleep, among other functions. Although serotonin is synthesized by the central nervous system, the majority is produced in the intestinal epithelium by enterochromaffin cells, suggesting its significant role in gastrointestinal regulation. While imbalances in serotonergic signaling are associated with gastrointestinal disorders such as irritable bowel syndrome and Crohn’s disease, the molecular and cellular mechanisms underlying this regulation remain poorly understood. Preliminary data from our group reveal that the Drosophila gut is innervated by serotonergic neurons, and that the absence of 5-HT increases food intake and defecation frequency, suggesting that serotonin plays a crucial role in gut regulation. In this study, we analyzed the feeding behavior, gut motility, and defecation rates of Trh-/- flies (serotonin-deficient), SerT-/- flies (serotonin excess), and flies deficient in each of the five serotonin receptors. While Trh-/- flies displayed increased food intake and defecation frequency, SerT-/- flies show a reduction in these parameters. Similar to Trh-/- flies, 5-HT7r-/- flies exhibited increased food intake and defecation frequency, suggesting that this receptor mediates serotoninergic regulation of gut functions and highlighting the importance of 5-HT in establishing gastrointestinal homeostasis.