Annual and Daily Changes in Brain Serotonin Content in Differentially Housed Mice

Valzelli, L.; Bernasconi, S.; Cusumano, Giacomo

doi:10.1159/000117587

Cited by 26 publications

(6 citation statements)

References 24 publications

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“…Evidence by Wurtman and Fernstrom (1974) that the daily increase in tryptophan precedes that of 5-HT by several hours, indicates that the results presented here are in accordance with those obtained by Valzelli et al (1977), where the changes in brain 5-HT with time of day, were shown to be less pronounced in isolated mice than in grouped controls.…”

Section: Discussionsupporting

confidence: 92%

Brain Tryptophan in Isolated Aggressive Mice

Miller¹,

Pachter²,

Valzelli³

1979

Neuropsychobiology

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Circadian variations in whole brain tryptophan level and food intake were investigated in both normally grouped and isolated male Albino-Swiss mice, maintained on a 12:12 light-dark regimen (lights on 08.00–20.00). A significant diumal rhythm in brain tryptophan level was evidenced only by grouped animals, in contrast to the relatively sustained and significantly lower tryptophan level found to exist in isolated mice. Significant, daily rhythms in food intake, for both isolated and grouped mice were found to exist, that were highly correlated in phase. Isolated mice, however, consistently demonstrated an increased food consumption throughout the 24-hour period. These results suggest that a possible alteration in tryptophan metabolism exists in isolated mice, as tryptophan, an essential amino acid, is obtained by mammals only through their diet.

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Section: Discussionsupporting

confidence: 92%

Brain Tryptophan in Isolated Aggressive Mice

Miller¹,

Pachter²,

Valzelli³

1979

Neuropsychobiology

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“…IAA showed more variability than 5HIAA. Rodent brain 5HT and 5HIAA can exhibit marked seasonal fluctuations (Valzelli et al, 1977), and this may be one of the sources of variability in control values of CSF indole acids in this study. Other unknown factors, related to the life history of the animals, may also be involved.…”

Section: Discussionmentioning

confidence: 76%

Indoleamine Metabolism in Rat Brain Studied Through Measurements of Tryptophan, 5‐Hydroxyindoleacetic Acid, and Indoleacetic Acid in Cerebrospinal Fluid

Young

Anderson

Purdy

1980

Journal of Neurochemistry

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Tryptophan, 5-hydroxyindoleacetic acid (SHIAA), and indoleacetic acid (IAA) were measured in rat cerebrospinal fluid (CSF) using highperformance liquid chromatography with fluorometric detection in order to study brain indoleamine metabolism. Previously we have shown that IAA in CSF is derived from tryptamine in the CNS. In this study our results indicated that the synthesis of both 5-hydroxytryptamine (5HT) and tryptamine varied with changes in brain tryptophan. After a tryptophan load, tryptamine synthesis increased much more than 5HT synthesis; under these circumstances, it can be of the same order of magnitude as 5HT synthesis. Studies with treatments that cause release of 5HT (reserpine and cold stress) indicated that tryptamine is not released with 5HT and is probably not stored in vesicles. Use of selective monoamine oxidase inhibitors suggested that results obtained in vitvo concerning the substrates for monoamine oxidase A and B apply in vivo. Thus, 5HT was acted on preferentially by the A enzyme, and tryptamine by the B enzyme. Measurement of IAA in brain, CSF, and plasma before and after probenecid indicated that there are active transport systems moving IAA from CSF and brain to blood, and from brain to CSF. Our data suggest that measurements of C S F IAA are a simple and convenient way of studying CNS tryptamine metabolism and should be applied clinically. Key words: Cerebrospinal fluid-5-Hydroxyindoleacetic acid-5-Hydroxytryptamine-Indoleacetic acid-Tryptamine-Tryptophan. Measurement of amine-related compounds inCSF is an important method for the study of biogenic amine metabolism in human CNS. Indoleamine metabolism has been studied through m e a s u r e m e n t s o f b o t h t r y p t o p h a n a n d 5hydroxyindoleacetic acid (5HIAA) in CSF. The concentration of tryptophan in CSF is a reasonably good index of its content in the CNS (Young et al., 1976) and brain tryptophan is an important determ i n a n t o f t h e r a t e o f s y n t h e s i s o f 5hydroxytryptamine (5HT) (Ashcroft et al., 1965).The CSF 5HIAA concentration reflects CNS 5HT turnover (Garelis et al., 1974;Ebert and Perlow, 1977) and many clinical studies have taken advan-tage of this fact. Recently, using a new highperformance liquid chromatographic (HPLC) method (Anderson and Purdy, 1979), we have shown that indoleacetic acid (IAA) in CSF is derived from another indoleamine, tryptamine, in the CNS (Young et al., 1979).The amount of information on IAA in CSF and the factors that might affect it is limited. One study reported its presence in human lumbar CSF using a gas chromatographic-mass spectrometric method (Bertilsson and Palmer, 1972). Another study showed that there was a significant positive correlation between IAA and SHIAA in lumbar CSF of depressed patients and that chronic treatment with From theThe present address of George M. Anderson is Child Study Center, Yale University, New Haven, Connecticut 065 10.Abbreviations used: SHIAA, 5-Hydroxyindoleacetic acid; HPLC, High-performance liquid chromatography; 5HT, 5-Hydroxytr...

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“…There was marked variation in the neurotransmitter content of different control brain areas between the experiments. As the presented experiments were performed over the time-course of a year, these variations may be explained by seasonal variations in the brain's monoamine contents, as reported by Kempf et al (1978) in hamsters and Valzelli et al (1977) in mice. Thus, given that rodent species do have comparable circadian rhythms, it seems likely that the longevity of the present series of studies may have lead to variation in the measured neurotransmitter content between the different experiments.…”

Section: Post Mortem Neurochemistrymentioning

confidence: 85%