serotonin

Overview

Serotonin, also known as 5-hydroxytryptamine (5-HT), is a biogenic monoamine that functions as a neurotransmitter, neuromodulator, and peripheral signaling molecule. It is synthesized from tryptophan through tryptophan hydroxylase-dependent pathways and is metabolized to 5-hydroxyindoleacetic acid (5-HIAA). In the central nervous system, serotonin helps regulate mood, anxiety, cognition, sleep, appetite, and pain processing, while in the gastrointestinal tract it contributes to motility and secretion. It also participates in platelet function and broader neuroimmune and gut-brain axis signaling.

In biomedical research, serotonin is often studied together with related pathways such as dopamine, glutamate, GABA, Indoleamine 2,3-dioxygenase 1, monoamine oxidase, and the NLRP3 inflammasome. Altered serotonin signaling is implicated in depression, migraine, constipation, neurodegenerative disease, and drug-induced neurotoxicity. Because of this broad physiological reach, serotonin is frequently used as a mechanistic readout in studies of host-microbe interactions, oxidative stress, mitochondrial dysfunction, and neurotransmitter imbalance.

Focus of Latest Publications

Recent publications have examined serotonin in several distinct biomedical contexts, most often as a readout of serotonergic signaling rather than as a direct therapeutic target. In neurobiology, a paper-based electrochemical aptasensor was developed to simultaneously detect dopamine and serotonin in human brain samples, with the goal of distinguishing healthy from Alzheimer’s disease tissue based on altered neurotransmitter levels. The assay used aptamer-mediated recognition and potential-resolved electrochemical discrimination to quantify both analytes on a single disposable electrode, supporting multiplexed neurochemical monitoring.

Several studies linked serotonin-related measures to gut-brain and stress-related biology. In neonatal mice exposed to maternal separation, changes in breast milk fatty acid composition were associated with altered gut microbiota, serum metabolites, and serotonin-related gene expression in the prefrontal cortex. Specifically, maternal separation was associated with elevated myristic acid in breast milk, reduced Akkermansia muciniphila in offspring, and decreased Tph2 and Htr1b expression in the prefrontal cortex; inosine supplementation selectively increased Htr1a expression. In a separate chronic restraint stress model, the polysaccharide PSLP-1 from Polygonatum sibiricum stems and leaves reduced depressive-like behaviors and was associated with restoration of tryptophan metabolism, including promotion of tryptophan hydroxylase-related 5-hydroxytryptamine synthesis, alongside gut microbiota remodeling.

Other recent work used serotonin as a biochemical marker in disease models. In Parkinson’s disease, sulforaphane treatment improved motor performance and dopaminergic neuron survival while normalizing the 5-HIAA/5-HT ratio in the striatum, alongside effects on the CBS-H2S axis, mitophagy, and NLRP3 inflammasome activation. In lung neuroendocrine neoplasms, tumor tissue was evaluated for serotonin expression as part of a broader hormone-secretion analysis; however, serotonin expression did not correlate with elevated 5-HIAA, whereas hormone secretion overall was associated with poorer survival. Finally, a rat brain study testing endogenous N,N-dimethyltryptamine reported no detectable endogenous DMT pool and little evidence that exogenous DMT was retained in serotonin terminals, arguing against a major serotonergic storage role for DMT in that model.

Key Publications

NEWJun Maternal separation-induced changes in breast milk fatty acid composition are associated with altered gut microbiota and serotonergic gene expression in neonatal mice. (Molecular biomedicine, 2026, PMID 42365549): "...and serotonin-related gene expression in the prefrontal cortex."
Jun Hormone secretion predicts poor prognosis in lung neuroendocrine neoplasms. (Endocrine-related cancer, 2026, PMID 42227353): "Tumour tissue was evaluated for serotonin and calcitonin expression."
Jun Polysaccharide PSLP-1 from Polygonatum sibiricum Stems and Leaves Alleviates Depressive-like Behaviors and Modulates Gut Microbiota and Tryptophan Metabolism along the Gut-Brain Axis. (Journal of agricultural and food chemistry, 2026, PMID 42212449): "PSLP-1 was also associated with restoration of tryptophan metabolism, characterized by suppression of the indoleamine 2,3-dioxygenase 1-mediated kynurenine pathway and promotion of tryptophan hydroxylase-related 5-hydroxytryptamine synthesis."
May Microbial regulation of serotonin: A boost for drug delivery. (Cell host & microbe, 2026, PMID 42127817): "Microbial regulation of serotonin: A boost for drug delivery."
May Label-free paper-based electrochemical aptasensor with tunable selectivity for assessing neurotransmitter imbalance in Alzheimer's disease. (Mikrochimica acta, 2026, PMID 42095905): "...simultaneous detection of extracellular dopamine (DA) and serotonin (SE) in human brain samples..."
Apr The H2S donor sulforaphane inhibits NLRP3 inflammasome activation by inducing mitochondrial autophagy and mitigating CBS-H2S axis damage in in-vitro and in-vivo models of Parkinson's disease. (Bioorganic chemistry, 2026, PMID 41797134): "...normalizing the DOPAC/DA and 5-HIAA/5-HT ratios."
May N,N-dimethyltryptamine (DMT) is neither formed nor retained in serotonin terminals in the rat brain. (Neuropharmacology, 2026, PMID 41672133): "Mammalian brain may contain an endogenous pool of the psychedelic substance N,N-dimethyltryptamine (DMT), which may act as a co-transmitter with serotonin (5-HT)."