Louzao Ojeda, María del CarmenCostas Sánchez, CeliaAbal Camaño, PaulaSuzuki, ToshiyukiWatanabe, RyuichiVilariño del Río, NataliaCarrera González, María CristinaBoente Juncal, AndreaVale González, María del CarmenRodríguez Vieytes, MercedesBotana López, Luis Miguel2021-07-292021-07-292021Louzao, M.C., Costas, C., Abal, P. et al. Serotonin involvement in okadaic acid-induced diarrhoea in vivo. Arch Toxicol 95, 2797–2813 (2021). https://doi.org/10.1007/s00204-021-03095-z0340-5761http://hdl.handle.net/10347/26635The consumption of contaminated shellfish with okadaic acid (OA) group of toxins leads to diarrhoeic shellfish poisoning (DSP) characterized by a set of symptoms including nausea, vomiting and diarrhoea. These phycotoxins are Ser/Thr phosphatase inhibitors, which produce hyperphosphorylation in cellular proteins. However, this inhibition does not fully explain the symptomatology reported and other targets could be relevant to the toxicity. Previous studies have indicated a feasible involvement of the nervous system. We performed a set of in vivo approaches to elucidate whether neuropeptide Y (NPY), Peptide YY (PYY) or serotonin (5-HT) was implicated in the early OA-induced diarrhoea. Fasted Swiss female mice were administered NPY, PYY(3–36) or cyproheptadine intraperitoneal prior to oral OA treatment (250 µg/kg). A non-significant delay in diarrhoea onset was observed for NPY (107 µg/kg) and PYY(3–36) (1 mg/kg) pre-treatment. On the contrary, the serotonin antagonist cyproheptadine was able to block (10 mg/kg) or delay (0.1 and 1 mg/kg) diarrhoea onset suggesting a role of 5-HT. This is the first report of the possible involvement of serotonin in OA-induced poisoningeng© The Author(s) 2021. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/Atribución 4.0 Internacionalhttp://creativecommons.org/licenses/by/4.0/Okadaic acidDiarrhoeic shellfish poisoning (DSP)5-HydroxytryptamineNeuropeptide YPeptide YYjournal article10.1007/s00204-021-03095-z1432-0738open access