Autoradiographic Measurement of the Rate of Serotonin Synthesis in the Rat Brain
The rate of serotonin synthesis has hitherto been measured by two different methodological approaches, steady- and nonsteady-state. In these methods, the rate of synthesis is estimated from the change in the concentration of a tryptophan metabolite after inhibition of an enzyme (tryptophan hydroxylase, aromatic amino acid decarboxylase (AAAD) or monoamine oxidase) or the inhibition of 5-hydroxyindoleacetic acid transport. These approaches can be challenged on the grounds that a feedback mechanism might have some effect on the measured synthesis rate. A major disadvantage of these methods is the necessity of separating different metabolites, a time-consuming process that generally requires tissue sampling, which is usually heterogeneous. Both pharmacological manipulation and tissue sampling have a profound effect on the estimation of the synthesis rates in all brain structures.
KeywordsTryptophan Hydroxylase Serotonin Synthesis Medial Raphe Nucleus Plasma Tryptophan Pineal Body
Unable to display preview. Download preview PDF.
- Bevington, P.R., 1969, “Data Reduction and Error Analysis for the Physical Sciences”, McGraw-Hill, New York, pp. 92–118.Google Scholar
- Nagahiro, S., Takada, A., Diksic, M., Sourkes, T.L., Missala, K., and Yamamoto, Y.L., 1990, A new method to measure brain serotonin synthesis in vivo. II. A practical autoradiographic method tested in normal and lithium-treated rats, J. Cereb. Blood Flow Metab., 10: 13–21.PubMedCrossRefGoogle Scholar
- Renson J., 1973, Assays and properties of tryptophan 5-hydroxylase, in: “Serotonin and Behavior”, Barchas J., and Usdin, E., eds., Academic Press, New York, pp. 19–32.Google Scholar
- Sokoloff, L., Reivich, M., Kennedy, C., Rosiers, H.D., Patlak, C.S., Pettigrew, K.D., Sakurada, O., and Shinohara, M., 1977, The [14C] deoxyglucose method for the measurement of local cerebral glucose utilization: theory, procedure, and normal values in the conscious and anesthetized rat, J. Neurochem., 28: 897–910.PubMedCrossRefGoogle Scholar