The present studies sought to investigate the effect of tryptophan alone or coadministration of tryptophan and ethanol on the interaction of central frontal cortex and dorsal raphe nucleus serotonergic functional activities by utilizing in vivo microdialysis. Tryptophan (50 mg/kg, i.p.) led to a significant increase in the levels of 5-HIAA, a metabolite of serotonin (5-HT), in the dorsal raphe ...

Carcinoid patients are diagnosed biochemically on the basis of increased urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA); urinary and platelet serotonin concentrations are considered to provide complementary information. Using established HPLC methods with fluorometric detection, we evaluated the clinical usefulness of measurements of urinary 5-HIAA and urinary, plasma, and platelet se...

OBJECTIVES This study was performed to search for changes in rat pineal function attributed to age and immunization with Freund's adjuvant. METHODS Young (2 months) and old (18-20 months) Wistar rats were injected s.c. with Freund's adjuvant or its vehicle. Eighteen days later, at the acute phase of arthritis, pineal concentration of serotonin (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), nore...

5-Hydroxyindoleacetic acid (5-HIAA) is a major metabolite of serotonin, generated via a two step process, involving monoamine oxidase A (MAO-A) and aldehyde dehydrogenase. Measurement of 5HIAA in combination with serotonin may offer insight into mechanisms underlying various clinical symptoms. The ratio of serotonin to 5-HIAA may be used to evaluate serotonin turnover and monoamine oxidase acti...

OBJECTIVE Early life events often lead to deficits in CNS serotonin function, which underlie a number of reoccurring psychopathological disorders. Studies using rhesus macaques have demonstrated that early maternal deprivation reduces CNS serotonin turnover, as measured by cisternal CSF 5-HIAA concentrations. In addition, individual differences in CSF 5-HIAA remain stable from the first year of...

Experimental tooth movement is known to induce characteristic delayed and continuous nociception. Nociceptive somatic stimuli activate endogenous pain control systems such as descending monoaminergic pathways, which modulate the transmission of ascending sensory messages. To test the hypothesis that bulbospinal serotonergic pathways modulate subchronic nociception, we assayed the medulla at the...

BACKGROUND Quantification of 5-hydroxyindole-3-acetic acid (5-HIAA) in urine is useful in diagnosing and monitoring of patients with carcinoid tumors and in the study of serotonin (5-hydroxytryptamine) metabolism in various disorders. We describe an automated method that incorporates on-line solid-phase extraction (SPE) and HPLC to measure urinary 5-HIAA. METHODS Automated prepurification of ...

Leptin administration inhibits diencephalic nitric oxide synthase (NOS) activity and increases brain serotonin (5-HT) metabolism in mice. We evaluated food intake, body-weight gain, diencephalic NOS activity, and diencephalic content of tryptophan (TRP), 5-HT, hydroxyindoleacetic acid (5-HIAA), and 5-HIAA/5-HT ratio after intracerebroventricular (ICV) or intraperitoneal (IP) leptin injection in...

8-hour urine excretions of 5-hydroxyindoleacetic acid (5-HIAA) were measured in 18 children with coeliac disease before treatment and the results expressed as microgram 5-HIAA/mg creatinine. Similar measurements were made on urine collections from an age-matched control group of 24 children. Significantly higher values of 5-HIAA excretion were found in children with untreated coeliac disease. M...