I. Theory and Basic Data for a Biological Model. M. Diksic, S. Nagahiro, ... Psychiatry and Biochemistry, McGill University, Montreal, Quebec, Canada. Summary: We ..... plasma free tryptophan and other amino acids com peting for the same ...
Journal of Cerebral Blood Flow and Metabolism 10:1-12 © 1990 Raven Press, Ltd., New York
A New Method to Measure Brain Serotonin Synthesis In Vivo. I. Theory and Basic Data for a Biological Model
M. Diksic, S. Nagahiro, *T. L. Sourkes, and Y. L. Yamamoto Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, and *Departments of Psychiatry and Biochemistry, McGill University, Montreal, Quebec, Canada
Summary: We describe here an autoradiographic method to measure the in vivo rate of serotonin synthesis in rat brain. The method is based on the use of the L-tryptophan analogue a-methyl-L-tryptophan (a-MTrp), which is con verted in vivo into a-methylserotonin (a-M5HT). Since a-M5HT is not a substrate for monoamine oxidase, it is accumulated in the brain tissue. Data are presented to confirm time-dependent conversion of a-MTrp into a-M5HT in the dorsal raphe nucleus and also in the pineal body, an organ outside the blood-brain barrier. It has also
been shown that washing brain slices in 10% trichloro acetic acid results in