scholarly journals A New Method to Measure Brain Serotonin Synthesis in vivo. II. A Practical Autoradiographic Method Tested in Normal and Lithium-Treated Rats

1990 ◽  
Vol 10 (1) ◽  
pp. 13-21 ◽  
Author(s):  
S. Nagahiro ◽  
A. Takada ◽  
M. Diksic ◽  
T. L. Sourkes ◽  
K. Missala ◽  
...  
Keyword(s):  
Tryptophan Hydroxylase ◽  
Lithium Treatment ◽  
Point Method ◽  
Synthesis Rate ◽  
Serotonin Synthesis ◽  
Autoradiographic Method ◽  
The Brain ◽  
Cerebral Structures ◽  
Time Point

We describe here a practical autoradiographic method to estimate the rate of serotonin synthesis in brain. A two-time point method (60 and 150 min after injection of a-[14C]methyl-l-tryptophan) was first evaluated in 14 normal rats (7 at each time point). After this the method was tested in lithium-treated rats. In normal rats the rate of serotonin synthesis measured by the two-time point method generally correlated with known concentrations of tryptophan hydroxylase. The rate of synthesis in lithium-treated rats was compared with that in shamtreated rats (NaCl treatment). The results showed a significant increase in the synthesis rate in some cerebral structures. The greatest increases in the serotonin synthesis rate, attributable to the lithium treatment, were observed in the parietal cortex (52%) and caudate nucleus (47%). This is the first investigation to demonstrate, with autoradiographic resolution (∼100 μm), the differential changes in the rate of serotonin synthesis in the brain. Lithium had no significant effect on the rate of synthesis in the pineal gland.

Serotonin synthesis rate and the tryptophan hydroxylase-2: G-703T polymorphism in social anxiety disorder

2016 ◽  
Vol 30 (10) ◽  
pp. 1028-1035 ◽  
Author(s):  
Tomas Furmark ◽  
Ina Marteinsdottir ◽  
Andreas Frick ◽  
Kerstin Heurling ◽  
Maria Tillfors ◽  
...  
Keyword(s):  
Anxiety Disorder ◽  
Social Anxiety ◽  
Social Anxiety Disorder ◽  
Tryptophan Hydroxylase ◽  
Synthesis Rate ◽  
Serotonin Synthesis ◽  
Tryptophan Hydroxylase 2

scholarly journals A New Method to Measure Brain Serotonin Synthesis in vivo. I. Theory and Basic Data for a Biological Model

1990 ◽  
Vol 10 (1) ◽  
pp. 1-12 ◽  
Author(s):  
M. Diksic ◽  
S. Nagahiro ◽  
T. L. Sourkes ◽  
Y. L. Yamamoto
Keyword(s):  
Trichloroacetic Acid ◽  
Brain Slices ◽  
Brain Structures ◽  
Pineal Body ◽  
Biological Model ◽  
Tracer Kinetics ◽  
Serotonin Synthesis ◽  
Precursor Pool ◽  
The Brain

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 converted 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% trichloroacetic acid results in <3% incorporation of a-MTrp into brain proteins. The rates of synthesis are calculated in several grossly dissected brain structures by using tracer kinetics and a three-compartment biological model. The half-life of the precursor pool is estimated to be ∼20 min. The rate of serotonin synthesis is highest in the pineal body.

Analysis of [C-11]Alpha-Methyl-Tryptophan Kinetics for the Estimation of Serotonin Synthesis Rate In Vivo

1997 ◽  
Vol 17 (6) ◽  
pp. 659-669 ◽  
Author(s):  
Otto Muzik ◽  
Diane C. Chugani ◽  
Pulak Chakraborty ◽  
Thomas Mangner ◽  
Harry T. Chugani
Keyword(s):  
Human Brain ◽  
Dynamic Equilibrium ◽  
Rank Order ◽  
Synthesis Rate ◽  
Serotonin Synthesis ◽  
Sensitivity Matrix ◽  
Acceptable Error ◽  
Patlak Plot ◽  
Functional Images

We describe the tracer kinetic analysis of [C-11]-labeled alpha-methyl-tryptophan (AMT), an analogue of tryptophan, which has been developed as a tracer for serotonin synthesis using positron emission tomography (PET) in human brain. Dynamic PET data were acquired from young healthy volunteers (n = 10) as a series of 22 scans covering a total of 60 minutes and analyzed by means of a three-compartment, four-parameter model. In addition, functional images of the K-complex were created using the Patlak-plot approach. The application of a three-compartment model resulted in low identifiability of individual k-values, especially that of k3. Model identifiability analysis using a singular value decomposition of the final sensitivity matrix showed parameter identifiability to increase by 50% when the Patlak-plot approach was used. K-complex values derived by the Patlak-plot approach overestimated the compartmental values by 10 to 20%, because of the violation of the dynamic equilibrium assumption. However, this bias was fairly constant in all structures of the brain. The rank order of K-complex values from different brain regions corresponded well to the regional concentrations of serotonin in human brain (P < 0.0001). These results indicate that the Patlak-plot method can be readily applied to [C-11]AMT data in order to create functional images of the K-complex, reflecting serotonin synthesis rate, within an acceptable error margin.

A simplified autoradiographic method with α-[14C]methyl-tryptophan to measure serotonin synthesis rate in the rat brain

2004 ◽  
Vol 31 (8) ◽  
pp. 1013-1019
Author(s):  
Hidehiko Okazawa ◽  
Sadahiko Nishizawa ◽  
Tatsuro Tsuchida ◽  
Yoshiharu Yonekura ◽  
Mirko Diksic
Keyword(s):  
Rat Brain ◽  
Synthesis Rate ◽  
Serotonin Synthesis ◽  
Autoradiographic Method
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