Neurochemistry: Serotonin and Clinical Disorders

1 In choosing a topic on which to conduct our senior research as members of the LaGrange College Department of Chemistry, we established a set of criteria against which each possible topic was evaluated. First, we sought topics on which we had little to no prior knowledge so that our time spent engaged in research would be both interesting and enlightening. Secondly, we looked for topics which would effectively relate clinical applications to our undergraduate course of study and that would, therefore, be beneficial as we leave the department and pursue careers in medicine.We also sought topics on which we could provide detailed information that would be relevant not only to the trained scientist, but to the casual reader as well. Through our academic endeavors as undergraduate students we have gained a broad background in the fields of psychology and biochemistry, both of which place some degree of emphasis on chemical processes in the brain. Having been exposed only to the basics of such processes in these courses, we developed a keen interest in the topic of neurochemistry.Though this topic is in itself extremely complex and continually developing, the existing links between serotonin and several neurological disorders provided a wide range of chemical and clinical applications into which we could delve. Furthermore, with serotonin being so closely associated with common neurological and psychological disorders, a body of work summarizing various serotonergic processes would, we feel, be beneficial to a broad spectrum of readers. Synthesis of serotonin – also called 5-hydroxytrypamine – begins with the conversion of the amino acid L-tryptophan to 5-hydroxytryptophan by the enzyme tryptophan-5-hydroxylase.1 L-tryptophan is one of the nine essential amino acids, meaning that it is not synthesized in the body and must be obtained from external sources through the diet.The daily minimum requirement, 200 mg, of L-tryptophan can be satisfied by taking in adequate amounts of protein rich foods (such as red meat, fish, dairy products, and poultry).2 Once taken into the body, tryptophan can undergo conversion to either niacin or serotonin, with step one of the conversion to serotonin.3 Tryptophan-5-hydroxylase – the enzyme involved in the first reaction in the synthesis of serotonin – can be inhibited by a variety of chemical compounds, Neurochemistry: Serotonin and Clinical Disorders ANDREW L. DODGEN AND B. NICOLE GONZALEZ