Table 5. Data on serotonin.

GI - gastrointestinal, IBS - irritable bowel syndrome

Study	Author/ reference no.	Year of publication	Type of study	Purpose of study	Results	Interpretation
The role of serotonin neurotransmission in gastrointestinal tract and pharmacotherapy molecules	Guzel et al. [7]	2022	Review	Identifying the role of serotonin in gut physiology and extrapolating its use to treat functional GI disorders.	Explain the role of serotonin in the gut-brain axis and IBS pathogenesis. Diarrhea-predominant IBS patients have high plasma serotonin levels and those with constipation-predominant IBS have low levels.	Serotonin agonists and antagonists and be used in IBS patients depending on their symptoms
Neurotransmitters: the critical modulators regulating gut-brain axis	Mittal et al. [6]	2017	Review	Illustrates the role of various neurotransmitters in gut physiology	Serotonin is a key regulator of gut immunity, motility, and inflammatory responses.	Serotonergic antagonists and agonists can be encouraged for the management of disorders of the gut-brain axis.