5-Hydroxy-l-tryptophan suppresses food intake in food-deprived and stressed rats
| Autor: | Jeff Breu, Timothy J. Maher, Richard J. Wurtman, Janine McDermott, Ahmed Amer |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Adult
Male medicine.medical_specialty Clinical Biochemistry Administration Oral Decarboxylase inhibitor Toxicology Biochemistry 5-Hydroxytryptophan Rats Sprague-Dawley Eating Behavioral Neuroscience chemistry.chemical_compound Stress Physiological Internal medicine medicine Animals Humans Biological Psychiatry Pharmacology chemistry.chemical_classification Analysis of Variance Aromatic L-amino acid decarboxylase Cross-Over Studies Tryptophan Brain Carbohydrate Rats Amino acid Endocrinology chemistry Female Serotonin Analysis of variance Food Deprivation Injections Intraperitoneal |
| Zdroj: | Pharmacology Biochemistry and Behavior. 77:137-143 |
| ISSN: | 0091-3057 |
| DOI: | 10.1016/j.pbb.2003.10.011 |
| Popis: | Giving L-tryptophan, serotonin's circulating precursor, or a serotonin-releasing drug can decrease food intake and body weight. Giving 5-hydroxy-L-tryptophan (5-HTP), serotonin's immediate intracellular precursor, has been thought to be ineffective in enhancing brain serotonin synthesis unless it is coadministered with a dopa decarboxylase inhibitor to protect 5-HTP from destruction outside the brain. We have examined the effect of 5-HTP on food consumption and tissue 5-HTP levels among rats subjected to two different hyperphagic stimuli, food deprivation and a standardized stress (tail pinch), and on plasma 5-HTP levels in humans. In rats, 5-HTP (3-200 mg/kg ip) suppressed food intake in a dose-dependent manner in both models, but was at least eight times more effective in our stress-hyperphagia model. (Differences in the two procedures might have contributed to the observed differences in potencies.) This suppression was blocked by coadministration of another large neutral amino acid (LNAA), L-valine. Brain 5-HTP levels correlated significantly with peak plasma 5-HTP (r(2)=.69) or 5-HTP/LNAA (r(2)=.81) levels. Additionally, among humans, oral 5-HTP (1.2-2.0 mg/kg) produced, after 1 and 2 h, a significant increase in plasma 5-HTP (1.5- to 2.3-fold). These observations suggest that 5-HTP may be useful in controlling the excessive food intake sometimes generated by stress, even if given without decarboxylase inhibitors or other drugs. |
| Databáze: | OpenAIRE |
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