Serotonin, also known as enteramine or 5-HT, belongs to the class of organic compounds known as serotonins. Serotonins are compounds containing a serotonin moiety, which consists of an indole that bears an aminoethyl a position 2 and a hydroxyl group at position 5. Serotonin is a very strong basic compound (based on its pKa). Serotonin exists in all living organisms, ranging from bacteria to humans. Within humans, serotonin participates in a number of enzymatic reactions. In particular, serotonin can be converted into serotonin through its interaction with the enzyme 5-hydroxytryptamine receptor 7. In addition, serotonin can be converted into serotonin through the action of the enzyme 5-hydroxytryptamine receptor 7. In humans, serotonin is involved in excitatory neural signalling through 5-htr 7 and serotonin. Outside of the human body, Serotonin is found, on average, in the highest concentration within a few different foods, such as sea-buckthornberries, common walnuts, and oats and in a lower concentration in swiss chards, nanking cherries, and dills. Serotonin has also been detected, but not quantified in, several different foods, such as fruits, bitter gourds, yellow wax beans, scarlet beans, and green bell peppers. This could make serotonin a potential biomarker for the consumption of these foods. Serotonin has three different modes of action in the nervous system: as transmitter, acting locally at synaptic boutons; upon diffusion at a distance from its release sites, producing paracrine (also called volume) effects, and by circulating in the blood stream, producing hormonal effects. Serotonin, with regard to humans, has been found to be associated with several diseases such as colorectal cancer, brunner syndrome, hypothyroidism, and eosinophilic esophagitis; serotonin has also been linked to the inborn metabolic disorder aromatic l-amino acid decarboxylase deficiency. Serotonin is also a microbial metabolite, urinary serotonin is produced by Candida, Streptococcus, Escherichia, and Enterococcus (PMID: 24621061 ). Not evaluated by the FDA, homeopathic product. For temporary relief of nervousness, anxiety, mood swings, joint pains, weakness, drowsiness, itching and lethargy. Serotonin is widely distributed in the nervous system of vertebrates and invertebrates and some of its behavioral effects have been preserved along evolution. In vertebrates, which display a wider and much more sophisticated behavioral repertoire, serotonin also modulates sleep, the arousal state , sexual behavior, and others, and deficiencies of the serotonergic system causes disorders such as depression, obsessive-compulsive disorder, phobias, posttraumatic stress disorder, epilepsy, and generalized anxiety disorder. Serotonin in the nervous system acts as a local transmitter at synapses, and as a paracrine or hormonal modulator of circuits upon diffusion, allowing a wide variety of "state-dependent" behavioral responses to different stimuli. Such is the case of aggressive behavior and rhythmic motor patterns , including those responsible for feeding.