A neurotransmitterSerotonin creatinine sulfate monohydrate has been used:• to study its effect on the feeding motions in Caenorhabditis elegans• to study the chronotropic responses of serotonin (5-HT) in the zebrafish heart• to study the effect of serotonin on isthmus peristalsis;A neurotransmitterSerotonin creatinine sulfate monohydrate has been used:• to study its effect on the feeding motions in Caenorhabditis elegans• to study the chronotropic responses of serotonin (5-HT) in the zebrafish heart• to study the effect of serotonin on isthmus peristalsis