Serotonin (5-hydroxytryptamine, 5-HT) is a monoamine neurotransmitter synthesized from the amino acid tryptophan by the enzyme tryptophan-decarboxylase. The 5-HT3 channel is a ligand gated ion channel receptor of the cys-loop channel family. It is a pentamer with five subunits surrounding a central channel¹.

Methyl Serotonin (2-Methyl-5-hydroxytryptamine hydrochloride) is an agonist of 5-HT3 receptors with an effective concentration of 0.5-50 µM and an IC50 of 3.1±0.9 µM and also a potent ligand of the 5-HT6 receptor, member of the G-protein coupled receptor superfamily. Methyl Serotonin mimics the action of 5-HT although it displays a low affinity to 5-HT1 and 5-HT2 receptors. Methyl Serotonin was found to stimulate the hydrolysis of phosphoinositide in rat brain tissue². In a study conducted in N1E-115 neuroblastoma cells, Methyl Serotonin elicited inward ion currents that were only 19.9±2.4% of currents elicited by regular Serotonin binding. These currents increase with higher concentration of Methyl serotonin. Desensitization of the 5-HT receptor after Methyl Serotonin binding was slower than equivalent Serotonin binding³.