Acid monoamine metabolites in human cerebrospinal fluid and their relations to age and sex

Cerebrospinal Fluid Homovanillic and 5-Hydroxyindoleacetic Acids in a Large Pediatric Population; Establishment of Reference Intervals and Impact of Disease and Medication

BACKGROUND

Cerebrospinal fluid (CSF) homovanillic (HVA), and 5-hydroxyindoleacetic acids (5-HIAA) are biomarkers of neurological diseases affecting the dopaminergic and serotoninergic pathways. Establishing reference intervals for these metabolites faces the challenges of a lack of healthy controls and a negative correlation with age, making stratified intervals unrealistic. We propose a pipeline to determine continuous reference intervals for HVA and 5-HIAA using an indirect method. We also studied the confounding effects of different variables and explored the impact of antiepileptic and neuroleptic treatments on HVA and 5-HIAA values.

METHODS

The study used least squares regression to fit age-concentration curves from a cohort of pediatric patients (n = 1533), where the residuals represent metabolite values excluding age effect. Presuming that HVA and 5-HIAA primary deficiencies characterize a distinct subpopulation, we fitted a two-component finite mixture model in age-normalized data and set reference intervals at the central 95% of the nondeficient population.

RESULTS

Patients with primary genetic deficiencies of HVA and/or 5-HIAA consistently fall outside the proposed continuous reference intervals. Using the new continuous reference intervals reduces the number of secondary deficiencies detected compared with using stratified values. No correlations were observed between CSF HVA and 5-HIAA values across the studied drug categories (antiseizure and neuroleptic medications). In addition, biopterin values positively influenced both metabolite concentrations.

CONCLUSION

The proposed continuous reference intervals caused a substantial reduction in the number of secondary deficiencies detected, most of which demonstrated no conclusive correlations between the diseases and altered HVA and 5-HIAA values.

Biomarkers in the cerebrospinal fluid of patients with psychotic disorders compared to healthy controls: a systematic review and meta-analysis

Psychotic disorders are severe mental disorders with poorly understood etiology. Biomarkers in the cerebrospinal fluid (CSF) could provide etiological clues and diagnostic tools for psychosis; however, an unbiased overview of CSF alterations in individuals with psychotic disorders is lacking. The objective of this study was to summarize all quantifiable findings in CSF from individuals with psychotic disorders compared to healthy controls (HC). Studies published before January 25th, 2023 were identified searching PubMed, EMBASE, Cochrane Library, Web of Science, ClinicalTrials.gov, and PsycINFO. Screening, full-text review, data extraction, and risk of bias assessments were performed by two independent reviewers following PRISMA guidelines. Findings in patients and healthy controls were compared and summarized using random-effects analyses and assessment of publication bias, subgroup and sensitivity analyses were performed. 145 studies, covering 197 biomarkers, were included, of which 163 biomarkers have not previously been investigated in meta-analyses. All studies showed some degree of bias. 55 biomarkers measured in CSF were associated with psychosis and of these were 15 biomarkers measured in ≥2 studies. Patients showed increased levels of noradrenaline (standardized mean difference/SMD, 0.53; 95% confidence interval/CI, 0.16 to 0.90) and its metabolite 3-methoxy-4-hydroxyphenylglycol (SMD, 0.30; 95% CI: 0.05 to 0.55), the serotonin metabolite 5-hydroxyindoleacetic acid (SMD, 0.11; 95% CI: 0.01 to 0.21), the pro-inflammatory neurotransmitter kynurenic acid (SMD, 1.58; 95% CI: 0.34 to 2.81), its precursor kynurenine (SMD,0.99; 95% CI: 0.60 to 1.38), the cytokines interleukin-6 (SMD, 0.58; 95% CI: 0.39 to 0.77) and interleukin-8 (SMD, 0.43; 95% CI: 0.24 to 0.62), the endocannabinoid anandamide (SMD, 0.78; 95% CI: 0.53 to 1.02), albumin ratio (SMD, 0.40; 95% CI: 0.08 to 0.72), total protein (SMD, 0.29; 95% CI: 0.16 to 0.43), immunoglobulin ratio (SMD, 0.45; 95% CI: 0.06 to 0.85) and glucose (SMD, 0.48; 95% CI: 0.01 to 0.94). Neurotensin (SMD, -0.67; 95% CI: -0.89 to -0.46) and γ-aminobutyric acid (SMD, -0.29; 95% CI: -0.50 to -0.09) were decreased. Most biomarkers showed no significant differences, including the dopamine metabolites homovanillic acid and 3,4-dihydroxyphenylacetic acid. These findings suggest that dysregulation of the immune and adrenergic system as well as blood-brain barrier dysfunction are implicated in the pathophysiology of psychotic disorders.

Impacts of age on plasma monoamine metabolite concentrations in a large cohort of healthy individuals

The measurement of plasma concentrations of monoamine metabolites is a useful method for inferring the dynamics of monoamine metabolites in the brain. To clarify effects of age and sex on plasma monoamine metabolites levels, we used high-performance liquid chromatography to measure plasma levels of homovanillic acid (HVA), free and total 3-methoxy-4-hydroxyphenylglycol (MHPG), and 5-hydroxyindoleacetic acid (5-HIAA) in healthy men and women of various ages (n=214). In all plasma monoamine metabolites, there were significant differences across the age groups, and multiple comparisons revealed that older subjects had higher levels than younger subjects. Moreover, significant positive correlations were found between age and plasma levels of HVA, free MHPG, total MHPG, and 5-HIAA. On the other hand, plasma concentrations of monoamine metabolites were not influenced by sex, except for total MHPG for which the plasma levels were significantly higher in men than in women. Age-related changes in monoamine oxidase and renal function might affect our results. This large cohort survey provides further evidence to be cautiously aware of age effects when regarding plasma monoamine metabolites levels as reflections of central activity.

Effect of age on cisternal cerebrospinal fluid concentrations of monoamine metabolites in nonhuman primates

There are conflicting reports of the effects of aging on human neurotransmitter systems as estimated by monoamine metabolite concentrations in cerebrospinal fluid (CSF). These discrepancies may be due to sampling site, age or sex of the subjects or other variables that affect CSF metabolite determinations. Cisternal CSF concentrations of homovanillic acid (HVA), 3-methoxy-4-hydroxyphenyl-ethylene glycol (MHPG) and 5-hydroxyindoleacetic acid (5-HIAA), major metabolites of dopamine, norepinephrine and serotonin, respectively, were measured in rhesus monkeys (Macaca mulatta) of two age groups. Concentrations of HVA and MHPG were significantly lower in the older group of monkeys, whereas no changes in 5-HIAA were found. This supports the hypothesis that brain catecholamine concentrations decline with age.

CSF 5-HIAA, attempted suicide and suicide risk in schizophrenia spectrum psychosis

INTRODUCTION

There is evidence for a relationship between low levels of 5-hydroxyindoleacetic acid (5-HIAA) in cerebrospinal fluid (CSF) and suicidal behavior in mood disorder. A relationship between CSF homovanillic acid (HVA) and suicidal behavior has not been completely established. Studies done in patients with schizophrenia spectrum psychosis suffer from small numbers, short periods of follow-up and the results are contradictory. The objective of this study was to investigate the relationship between levels of CSF 5-HIAA, CSF HVA and suicidal behavior in patients with schizophrenia spectrum psychosis.

METHOD

Three hundred eighty five patients with schizophrenia spectrum psychosis admitted to the Karolinska University Hospital between 1973 and 1987 were lumbar punctured in standardized manner. Patients were followed until 2006 for a median of 26 years. Information about prior suicide attempt was retrieved from medical records and causes of death were obtained from the Causes of Death Register at the National Board of Health and Welfare.

RESULTS

At the end of the follow-up 26 patients (6.8%) had died by suicide. Male gender (OR=3.5) and attempted suicide (OR=12.4) were risk factor for suicide when combined. There were no significant correlations between levels of CSF 5-HIAA, CSF HVA, HVA/5-HIAA ratio and attempted, violent or non-violent suicide.

CONCLUSION

Male schizophrenia spectrum psychosis patients with prior suicide attempt are at high risk for suicide. No correlation between CSF monoamine metabolites levels and suicidal behavior was found. Suicidal behavior in schizophrenia spectrum psychosis may not, in contrast to mood disorders, be predicted by levels of CSF 5-HIAA and HVA.

Factors influencing the occurrence of "on-off" symptoms during long-term treatment with L-dopa

"On-off" symptoms were found to have developed in 43 of 85 parkinsonian patients who had been treated with L-dopa for five years or more, the risk of such symptoms apparently being greater the younger the patient had been at the début of the disease and at the start of treatment. The dopa dose had been higher throughout the treatment in the patients developing "on-off" symptoms than in those maintaining an even effect, and, furthermore, the initial improvement had been more marked and dyskinesia had appeared earlier and in a higher frequency. The clinical observations in the present studies seemed to be related to some pharmacological findings, where different degrees of the nigrostriatal neuron degeneration and the efficacy of the remaining neurons could be of importance for a varying therapeutic response. It also seemed possible that a higher dopa dose could evoke "on-off" symptoms more easily than a lower one in thereto predisposed individuals. As the patients maintaining an even symptomatology during long-term treatment with L-dopa were older, and in particularly as they had dementia in a higher frequency than those developing "on-off" symptoms, the possibility of a more widespread neuron damage, influencing the clinical manifestation in these patients, had to be taken into consideration.

CSF serotonin, 5-hydroxyindolacetic acid and neuropeptide Y levels in severe major depressive disorder

Serotonin (5-HT) and 5-hydroxyindolacetic acid (5-HIAA) have been the putative markers of MDD. Neuropeptide Y (NPY) may have an important role in the pathophysiology of major depressive disorder (MDD). However, direct measures of cerebrospinal fluid (CSF) 5-HT and NPY in severe MDD have been lacking. In the present study, we examined CSF 5-HT, 5-HIAA and NPY levels and correlate them with gender and suicidal behavior of severe major depressive disorder. Forty drug-free subjects with a severe major depressive disorder and forty control subjects underwent lumber puncture and psychiatric evaluation. Cerebrospinal fluid levels of 5-HT, 5-HIAA and NPY were assayed by enzyme-linked immunosorbent assay (ELISA) test. The relationships among 5-HT, 5-HIAA, NPY and clinical variables were statistically evaluated. There were no differences between severe major depressive disorder and controls in all parameters measured. In severe MDD group, significantly lower CSF 5-HT and higher 5-HT turnover (5-HIAA/5-HT) were found in female patients compared with male patients. The patients with intense suicidal intents and suicidal attempts had significantly lower CSF 5-HT compared to patients with nonsuicidal intents. Additionally, significantly lower CSF NPY was found in first episode depressed patients compared with recurrent depressed patients. Gender-related difference in CSF 5-HT implied a female preponderance in major depression to some extent. Cerebrospinal fluid 5-HT levels and 5-HT turnover (5-HIAA/5-HT) could be valuable tools for prediction of suicidality and potential markers for evaluating major depressive disorder. NPY was perhaps a marker for first episode depression.

Age-related changes in the visual cortex: a review

The main age related changes in visual cortex are reviewed. The visual cortex (occipital cortex, areas 17-19) undergoes a variety of anatomical, biochemical and functional changes with aging. From a morphological point of view the visual cortex loses nerve cells mainly in the last period of life. From a biochemical point of view cholinergic, serotonergic, and GABAergic neurotransmissions seem to be the most remarkably affected. In terms of functional correlates, a decline of several activities of the visual cortex has been documented in the elderly. Due to the importance of visual cortex in the realization of visual function, the influence of aging on this cerebrocortical area requires a more detailed analysis.

Serial cerebrospinal fluid tryptophan and 5-hydroxy indoleacetic acid concentrations in healthy human subjects

The role of the serotonergic system in the pathogenesis of behavioral disorders such as depression, alcoholism, obsessive-compulsive disorder, and violence is not completely understood. Measurement of the concentration of neurotransmitters and their metabolites in cerebrospinal fluid (CSF) is considered among the most valid, albeit indirect, methods of assessing central nervous system function in man. However, most studies in humans have measured lumbar CSF concentrations only at single time points, thus not taking into account rhythmic or episodic variations in levels of neurotransmitters, precursors, or metabolites. We have continuously sampled lumbar CSF via subarachnoid catheter in 12 healthy volunteers, aged 20-65 years. One ml (every 10 min) CSF samples were collected at a rate of 0.1ml/min for 24-hour (h), and the levels of tryptophan (TRP) and 5-hydroxy indoleacetic acid (5-HIAA) were measured. Variability across all 12 subjects was significantly greater (P < 0.0001) than the variability seen in repeated analysis of a reference CSF sample for both 5-HIAA (32.0% vs 7.9%) and TRP (25.4% vs 7.0%), confirming the presence of significant biological variability during the 24-hr period examined. This variability could not be explained solely by meal related effects. Cosinor analysis of the 24-hr TRP concentrations from all subjects revealed a significant diurnal pattern in CSF TRP levels, whereas the 5-HIAA data were less consistent. These studies indicate that long-term serial CSF sampling reveals diurnal and biological variability not evident in studies based on single CSF samples.

Cerebrospinal fluid biogenic amine metabolites, plasma-rich platelet serotonin and [3H]imipramine reuptake in the primary fibromyalgia syndrome

BACKGROUND

Primary fibromyalgia syndrome (PFS) is a chronic disorder commonly seen in rheumatological practice. The pathophysiological disturbances of this syndrome, which was defined by the American College of Rheumatology in 1990, are poorly understood. This study evaluated, in 30 patients, the hypothesis that PFS is a pain modulation disorder induced by deregulation of serotonin metabolism.

OBJECTIVES

To compare platelet [(3)H]imipramine binding sites and serotonin (5-HT) levels in plasma-rich platelets (PRP) of PFS patients with those of matched healthy controls and to compare the levels of biogenic amine metabolites in the cerebrospinal fluid (CSF) of PFS patients with those of matched controls.

METHODS

Platelet [(3)H]imipramine binding sites were defined by two criteria, B(max) for their density and K(d) for their affinity. PRP 5-HT and CSF metabolites of 5-HT (5-hydroxyindoleacetic acid, 5-HIAA), norepinephrine (3-methoxy, 4-hydroxy phenylglycol, MHPG) and dopamine (homovanillic acid, HVA) were assayed by reversed-phase high-performance liquid chromatography with coulometric detection.

RESULTS

[(3)H]Imipramine platelet binding was similar (P=0.43 for B(max) and P=0.30 for K(d)) in PFS patients (B(max)=901+/-83 fmol/mg protein, K(d)=0.682+/-0.046) and in matched controls (B(max)=1017+/-119 fmol/mg protein, K(d)=0.606+/-0.056). PRP 5-HT was significantly higher (P=0.0009) in PFS patients (955+/-101 ng/10(9) platelets) than in controls (633+/-50 ng/10(9) platelets). When adjusted for age, the levels of all CSF metabolites were lower in PFS patients. The CSF metabolite of norepinephrine (MHPG) was lower (P:=0.003) in PFS patients (8.33+/-0.33 ng/ml) than in matched controls (9.89+/-0.31 ng/ml) and 5-HIAA was lower (P=0.042) in PFS female patients (22.34+/-1.78 ng/ml) than in matched controls (25.75+/-1.75 ng/ml). For HVA in females, the difference between PFS patients (36.32+/-3.20 ng/ml) and matched controls (38.32+/-2.90 ng/ml) approached statistical significance (P=0.054).

CONCLUSION

Changes in metabolites of CSF biogenic amines appear to be partially correlated to age but remained diagnosis-dependent. High levels of PRP 5-HT in PFS patients were associated with low CSF 5-HIAA levels in female patients but were not accompanied by any change in serotonergic uptake as assessed by platelet [(3)H]imipramine binding sites. These findings do not allow us to confirm that serotonin metabolism is deregulated in PFS patients.

CSF 5-HIAA levels are lower in impulsive as compared to nonimpulsive violent suicide attempters and control subjects

BACKGROUND

We studied CSF 5-HIAA and HVA concentrations in violent suicide attempters and examined their relationship with depression, anxiety, and impulsivity.

METHODS

CSF 5-HIAA and HVA concentrations were determined very shortly after hospital admission and compared to those of a matched control population. Clinical evaluation was performed concomitantly; the level impulsivity was evaluated by the Impulsivity Rating Scale (IRS).

RESULTS

Twenty-three patients and 23 control subjects were included. According to the IRS, 14 patients were classified as impulsive, including all patients suffering from personality disorders, and 9 as nonimpulsive, with a main DSM-IIIR diagnosis of melancholia. CSF 5-HIAA concentrations in the suicide group were significantly lower than in control subjects. This difference was entirely due to the impulsive suicide attempters. There was an inverse correlation between the IRS score and CSF 5-HIAA (r = -.47, p = .02) and only a trend for HVA (r = -.41, p = .078) levels in the suicide group.

CONCLUSIONS

This study of a group of violent suicide attempters distinguished a subgroup of patients diagnosed with personality disorder with high impulsivity scores and a subgroup of patients with the main diagnosis of severe depression. CSF 5-HIAA was significantly lower in impulsive violent attempters than in nonimpulsive violent attempters, therefore desintangling violence from impulsivity and linking this biologic abnormality to impulsivity.

Neurotransmitters and suicidal behavior. The evidence from cerebrospinal fluid studies

Studies of neurotransmitter metabolites in cerebrospinal fluid (CSF) were initially focused on depressive illness. Although several studies have demonstrated low concentrations of the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA), and the dopamine metabolite, homovanillic acid (HVA), in depressed patients, these early studies may have been biased by concomitant administration of antidepressant drugs (which tend to lower CSF 5-HIAA), amount of CSF drawn (there is a concentration gradient for both metabolites), and selection of control subjects. Once these methodological details are controlled for, the differences between depressed patients and controls are unimpressive. However, there is a remarkably consistent association between low concentrations of CSF 5-HIAA and suicidal behavior, as evidenced by over 20 studies. The association is not confined to depressive illness but has also been found in schizophrenia, personality disorder, and certain impulse control disorders (but, interestingly, not in bipolar disorder). A low concentration of CSF 5-HIAA in a suicide attempter is associated with a substantial increase in short-term suicide risk. CSF studies in violent criminals, and in nonhuman primates, suggest that aggression dyscontrol may partly explain the association between suicide and serotonin, which is of considerable theoretical interest. CSF 5-HIAA determinations may also be helpful in the clinical assessment of suicide risk.

Reversal of an acute parkinsonian syndrome associated with multiple sclerosis by application of weak electromagnetic fields

The occurrence of movement disorders and particularly Parkinsonian symptoms is uncommon in patients with multiple sclerosis (MS) despite the rather frequent presence of demyelinating plaques in the basal ganglia. This disparity between the occurrence of clinical symptoms in MS and the distribution of demyelinating plaques suggests that impairment of neurotransmitter functions rather than demyelination may be critical to the clinical manifestations of the disease. A 48 year old woman with remitting-progressive MS developed a bilateral Parkinsonian syndrome in association with acute emotional stress which resolved after she received two brief successive extracerebral applications of low frequency picotesla flux density electromagnetic fields (EMFs). It is believed that in this patient Parkinsonism may have existed in a subclinical form and that acute stress, which previously has been shown to precipitate symptoms of Parkinson's disease, triggered the onset of Parkinsonism by further reducing dopaminergic and serotonergic neurotransmission in the basal ganglia. The rapid reversal of the Parkinsonian syndrome by EMFs was related to a presumed augmentation of dopaminergic and serotonergic neurotransmission which, on the basis of CSF studies, is reduced in chronic MS patients. The efficacy of EMFs in the treatment of Parkinson's disease had been documented previously but this report demonstrates that this treatment modality is beneficial also for the treatment of Parkinsonism developing in the setting of other neurodegenerative disorders.

Monoamine precursors, transmitters and metabolites in cerebrospinal fluid: a prospective study in healthy male subjects

In order to elucidate methodological aspects of CSF investigations, 14 healthy male subjects were lumbar-punctured at the L4-5 level following a standardised procedure. CSF concentrations of precursors, transmitters and transmitter metabolites were used as dependent variables, while age, height, body weight, atmospheric pressure and some other factors served as independent variables. 5-HIAA and HVA (but not HMPG) have pronounced concentration gradients. We also found CSF gradients for the precursors tryptophan and tyrosine, as well as for serotonin, dopamine and the dopamine metabolite DOPAC. Dopamine and atmospheric pressure showed a positive intercorrelation. Age correlated curvilinearly (convex upward) with tryptophan but showed a negatively directed linear correlation with serotonin. Serotonin and 5-HIAA showed no intercorrelation. Our results suggest an age-dependent disposition of tryptophan in the CSF. The absence of a correlation between serotonin and 5-HIAA might be inconsistent with the notion that 5-HIAA is a marker of central serotonin turnover. The comparatively high body weight of our volunteers might explain the lack of a gradient for HMPG.

The influence of aging on the plasma concentration and renal clearance of homovanillic acid

Using percutaneously placed arterial and venous catheters, we examined the influence of aging on the plasma concentration, whole body production rate, and renal clearance of homovanillic acid (HVA) in 60 healthy adult volunteers. The arterio-renal fractional extraction of HVA combined with the renal plasma flow (Fick Principle) were used to estimate the whole body HVA production rate and the renal plasma HVA clearance. The arterial HVA plasma concentration, whole body rate of HVA production, and HVA plasma clearance were determined to be 54 +/- 3 nmol/l, 27 +/- 2 nmol/min and 502 +/- 32 ml/min, respectively. The resting arterial HVA plasma concentration was positively correlated with aging, with the increased HVA concentrations in the older subjects being due to a diminished renal HVA plasma clearance. The diminished clearance of HVA occurred in response to a decreased renal plasma flow; the fractional extraction of HVA across the kidney remained unchanged with aging. This study emphasises the need for using age-matched control groups in neurochemical and neuropsychiatric studies, and demonstrates that increases in the arterial level of HVA do not necessarily reflect an increased rate of HVA production but may arise due to a diminished excretion rate of HVA from the body.

A meta-analysis of homovanillic acid concentrations in schizophrenia

The results of several experiments in which homovanillic acid (HVA) concentrations were measured, mainly in the cerebrospinal fluid, of schizophrenics are examined using Fisher's combination procedure. It is found that the data does not support the claim that the level of this dopamine catabolite is raised whereas some evidence strongly supports the claim that it is actually lowered. This finding is discussed in relation to the hypothesis of dopaminergic neuronal hyperactivity in schizophrenia.

The effect of age on concentrations of monoamines, amino acids, and their related substances in the cerebrospinal fluid

We studied age-related changes in the concentrations of monoamines, amino acids, and their related substances in the cerebrospinal fluid on 144 neurologically normal subjects. The concentrations of tyrosine, 3-O-methyldopa, dopamine (total), norepinephrine (total), homovanillic acid, p-hydroxyphenylacetic acid, and 5-hydroxytryptophan increased significantly with age (p < 0.05), and the concentration of 3.4-dihydroxyphenylacetic acid displayed a non-significant trend to decrease, whereas concentrations of other monoamine precursors and metabolites were unchanged. We found the significant positive correlations between the concentrations of HVA and 5-HIAA (p < 0.001), between tyrosine and tryptophan (p < 0.001), and between tyrosine and 3-O-methyldopa (p < 0.001). The concentrations of asparagine, glycine, taurine, and alanine increased significantly with age (p < 0.05), while glutamine, arginine, and threonine concentrations did not change with age. The aspartate, glutamate, and GABA concentrations displayed the non-significant trends to decrease in the elderly subjects. The concentrations of aspartate, glutamate, and GABA had mutually significant positive correlations (p < 0.05), but had significant negative correlations with the concentrations of some neutral amino acids. The urate and xanthine concentrations increased significantly with age (p < 0.01). These findings suggest that the concentrations of monoamine and amino acid transmitters and their related compounds in the cerebrospinal fluid reflect age-related changes in the synthesis, release, and reuptake mechanisms of the transmitters and their transport mechanisms across the blood-brain barrier.

Cerebrospinal fluid monoamine metabolites in fluoxetine-treated patients with major depression and in healthy volunteers

Cerebrospinal fluid (CSF) levels of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), 3-methoxy-4-hydroxyphenylglycol (MHPG), and homovanillic acid (HVA) were measured in three groups: 46 healthy volunteers; 9 medication-free patients with DSM III-R major depressive disorder, recurrent; and these same 9 patients following at least 4 weeks of fluoxetine treatment at 20 mg/day. CSF monoamine metabolite levels in medication-free patients did not differ from healthy volunteers; however, CSF 5-HIAA and MHPG decreased significantly from 95.9 +/- 24.6 (all values +/- SD) to 64.2 +/- 26.1 pmol/ml and from 46.7 +/- 14.2 to 42.6 +/- 11.6 pmol/ml, respectively, following fluoxetine treatment. Fluoxetine also significantly decreased mean Hamilton Depression Rating Scale scores from 23.2 +/- 6.5 to 17.4 +/- 5.0 and significantly increased the CSF HVA/5-HIAA ratio.

Cerebrospinal fluid monoamine metabolites in 114 healthy individuals 18-88 years of age

Concentrations of the monoamine metabolites homovanillic acid (HVA), 5-hydroxy-indoleacetic acid (5-HIAA) and 4-hydroxy-3-methoxyphenylglycol (HMPG) were determined in lumbar cerebrospinal fluid (CSF) of 114 healthy individuals, 18-88 years of age, without histories, symptoms or signs of central nervous system dysfunction. The mean values (+/- SD) were 253 +/- 109 nmol/l for HVA, 125 +/- 54 nmol/l for 5-HIAA, 47 +/- 10 nmol/l for HMPG, and 2.10 +/- 0.52 for the HVA/5-HIAA ratio. Analyses of confounding factors revealed that all metabolites correlated negatively with body height, the values being lower in taller than in shorter individuals. This is probably attributable to a larger surface area for monoamine metabolite transport from the subarachnoid space in taller than in shorter individuals. These correlations make statistical adjustment for body height important in analyses of monoamine metabolite levels. Without considering body height, all monoamine metabolites showed a positive correlation with age, and higher levels of HVA and 5-HIAA were found in women than men. After statistical adjustment for the influence of body height, no differences in CSF monoamine metabolites levels were found between the sexes, and only 5-HIAA showed a positive correlation with age. There were no significant seasonal variations for any of the monoamine metabolites.

Concentration gradients for monoamine metabolites in lumbar cerebrospinal fluid

Concentration gradients in lumbar cerebrospinal fluid (CSF) for the monoamine metabolites homovanillic acid (HVA), 5-hydroxy-indoleacetic acid (5-HIAA) and 4-hydroxy-3-methoxyphenylglycol (HMPG) were studied in 9 healthy controls and 47 neuropsychiatric patients without diseases causing disturbed CSF circulation. In a serial sampling of the first 24 ml of CSF, steep concentration gradients between the first (0-4th ml) and last (21st-24th ml) portions of CSF were found for HVA (99 +/- 59% increase; p < 0.001) and 5-HIAA (88 +/- 54% increase; p < 0.001), while the concentration gradient was slight for HMPG (11 +/- 7% increase; p < 0.001). The existence of marked concentration gradients for the monoamine metabolites HVA and 5-HIAA gives further evidence for an active transport system for these metabolites and indicates that the lumbar CSF-HVA and 5-HIAA levels reflect the dopamine and serotonin metabolism in the brain. Moreover, the existence of pronounced concentration gradients for HVA and 5-HIAA stresses the importance of making analyses on a standardized volume of CSF.

Monoamines and CSF: relevance to neuropsychiatric disorders

Over the past 25 years much effort has been put into the research of the relationship between neuropsychiatric disorders and the concentrations of CSF-monoamine metabolites. Most of this research has beenfocused on the relation between CSF-concentrations of 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) and specific symptomatological entities, particularly schizophrenia, Alzheimer's dementia and endogenous depression. It appeared that specific relations between diseases and CSF-concentrations of monoamine metabolites cannot be longer maintained and that a more functional psychopathology should be considered as the future research strategy.

Serotonergic measures in suicide brain: the concentration of 5-HIAA, HVA, and tryptophan in frontal cortex of suicide victims

Concentrations of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and tryptophan (TRP) were determined in the frontal cortex of individuals who died by suicide, homicide, accident, or the result of physical diseases. Females had significantly higher tryptophan concentrations than males. There was a significant correlation HVA and the interval between death to refrigeration of the body. Mean HVA levels were higher from noon to 5 PM. Suicide and homicide victims had significantly higher cortical HVA concentrations than those who died of physical disease but not accident victims. This was not accounted for by gender, age, postmortem interval from death to refrigeration of the body or to autopsy, specimen storage time, or drug effects. The ratio of HVA/5-HIAA was also significantly higher in suicides compared with those who died of physical disease. No differences in cortical 5-HIAA or tryptophan concentrations between the four groups were found. There were no differences in the levels of the three substances in violent and nonviolent suicides. There were no significant correlations between 5-HIAA, HVA and TRP concentrations in all subjects or any of the four subgroups. The implications of these findings for the role of serotonin and dopamine in suicide and violence are discussed.

Monoaminergic and cholinergic synaptic markers in the nucleus basalis of meynert (nbM): Normal age-related changes and the effect of heart disease and Alzheimer's disease

Neurotransmitter markers for acetylcholine, serotonin (5-HT), and dopamine (DA) were measured in autopsied human nucleus basalis of Meynert (nbM) from nondemented individuals without heart disease (non-HD) (age range, 4-84 years; n = 77), nondemented individuals with heart disease (HD) (age range, 57-92 years; n = 23), and individuals with Alzheimer's disease (AD) (age range, 59-92 years; n = 22). No significant differences in any chemical marker were found between age-matched HD and non-HD individuals. The activities of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE), and [3H]spiperone binding were regionally distributed within the nbM in control (non-HD) subjects less than 54 years of age. The activity of AChE, 5-[3H]HT binding, and the content of homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and 5-HT were regionally distributed in the nbM in non-HD, HD, and AD subjects more than 54 years of age. The binding of [3H]spiperone was regionally distributed in the nbM in HD and AD subjects more than 54 years of age, only. Activity of ChAT and AChE, content of 5-HT, 5-HIAA, and DA, binding of 5-[3H]HT, and the turnover number for DA (ratio of HVA/DA) all decreased with increasing age in the non-HD control population. The content of HVA, binding of [3H]spiperone, and the turnover number for 5-HT (ratio of 5-HIAA/5-HT) did not change with increasing age. Significant reductions in ChAT and AChE activities were found in AD nbM compared with postmortem interval- and age-matched HD and non-HD individuals. The reduction of 5-HT and 5-HIAA content and [3H]spiperone binding in individuals with AD of all ages suggests a loss of functional serotonergic innervation of the nbM. Dopaminergic synaptic markers were less affected in AD nbM, although turnover numbers for both DA and 5-HT were increased in AD. Receptor upregulation in response to presynaptic deficits did not occur for DA or 5-HT.

Urinary indoleamines in Tourette syndrome patients with obsessive-compulsive characteristics

Tourette syndrome patients with high levels of obsessive-compulsive symptoms were compared with patients without these symptoms on urinary measures of serotonin and its major metabolite, 5-hydroxyindoleacetic acid (5HIAA). Both groups were compared with normal controls, and it was hypothesized that patients with obsessive-compulsive symptoms would have lower levels of serotonin. Both groups of Tourette syndrome patients had lower levels than controls, but there was no difference between them. Obsessive symptoms were related to higher levels of 5HIAA and to a higher turnover of serotonin.

CSF monoamine metabolites in old age dementias

Cerebrospinal Fluid (CSF) levels of the main metabolites of monoamines (MHPG, 5-HIAA, and HVA) were measured in patients with early onset (AD) and late-onset (SDAT) Alzheimer's disease, vascular dementia (VD), and elderly controls. Psychobehavioral assessment was carried out by means of MMSE and GBS. Mean MHPG levels did not differ from controls; 5-HIAA was lower in VD when compared to both controls and SDAT. HVA was decreased in AD, SDAT, and VD with respect to controls. Significant correlations between HVA and psycho-behavioral parameters were observed in SDAT and VD groups, whereas no relationship was documented in AD. The SDAT group was divided in SDAT-A (age at onset: greater than 65 less than or equal to 80 yr) and SDAT-B (age at onset: greater than 80 yr). SDAT-A had significantly lower CSF HVA values than SDAT-B (165 +/- 64 vs 235.7 +/- 85). SDAT-B HVA levels were similar to those observed in controls. Correlation analysis between HVA and neuropsychological variables was significant in SDAT-A, but not in SDAT-B. These results might support the evidence of SDAT heterogeneity.

Limbic/mesolimbic connections and the pathogenesis of schizophrenia

The development of models of the pathogenesis of neuropsychiatric diseases that build on recent advances in chemical neuroanatomy will help to guide future research. The interconnections among limbic, basal ganglia, and cortical structures are used to form the basis of a hypothesis of the pathogenesis of schizophrenia. The adaptive capacity of subcortical dopamine systems is advanced as an explanation of the many states of the disease.

Neurotransmitter markers in the cerebrospinal fluid of normal subjects. Effects of aging and other confounding factors

We have investigated neurotransmitter-related markers of the cerebrospinal fluid (CSF) in a carefully screened series of normally aging subjects in standardized conditions in order to find out the influence of age and other confounding factors on CSF measures. The levels of 3-methoxy-4-hydroxyglycol (MHPG) and the activity of acetylcholinesterase (AChE) also increased with age, while homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5 HIAA) and immunoreactivities of somatostatin (SLI), beta-endorphin (BLI) and adrenocorticotropic hormone (ACTH) were unrelated to age. The gender of subjects had no significant effect on the levels of neurotransmitter markers, while seasonal changes, as well as height and weight of the subjects seemed to cause some variations in the levels of HVA, dopamine-beta-hydroxylase (DBH) and ACTH. The study underscores the importance of standardized conditions and matched patient groups in the CSF studies.

Effect of aging on dopamine metabolism in the rat cerebral cortex: a regional analysis

Age-related changes in the levels of dopamine (DA) and its metabolites were measured in seven cerebral cortical areas and in the striatum of 3, 10 and 27 month-old Sprague-Dawley rats. An age-related increase in DA levels was observed in the somatomotor (SM) cortex. In contrast, a decrease was observed in the temporal (T) cortex. Decreases in homovanillic acid (HVA) levels were observed in prelimbic (PL), pyriform (PY) and T cortex of aged rats, whereas significant increases in the levels of 3-methoxytyramine (3-MT) were observed in PL, prefrontal (PF), cingulate (C) as well as in T cortex. In the striatum, DA and HVA were decreased but the level of 3-MT remained unchanged. Norepinephrine (NE) levels increased in rats from 3 to 27 months in all the cortical areas. The increase in the levels of the DA extraneuronal metabolite, 3-MT, confirms our previous results showing that the release of DA might be increased with age in some cortical areas. The present results show that there is no general age-related decrease in the level of monoamines and of their metabolites in the rat cerebral cortex and that the changes display a complex, area-specific pattern.

Neuroleptic malignant syndrome: a study of CSF monoamine metabolism

In 8 cases of typical neuroleptic malignant syndrome (NMS), homovanillic acid (HVA), 5-hydroxyindole acetic acid (5-HIAA), noradrenaline (NA), and 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) levels in the cerebrospinal fluid (CSF) were assayed during both the active phase of NMS and after recovery. Compared with levels in normal control subjects the levels of HVA were significantly lower in patients with active NMS. This finding supports the central dopamine blockade theory of NMS pathophysiology. In addition, the levels of HVA were significantly decreased after recovery, suggesting that there may be a decreased dopamine metabolism in patients susceptible to NMS. The levels of 5-HIAA in patients with active NMS and after recovery were also significantly lower than those in normal control group, suggesting a relationship between the development of NMS and a disturbance of serotonin metabolism. The levels of NA in patients with active NMS were significantly higher than in normal subjects, and were within normal range after recovery. The levels of MHPG had a tendency to increase in patients with active NMS, compared with levels during recovery. These findings are a result of increased sympathetic nervous system activity in patients with active NMS; however, they are also observed in other disorders and may well reflect the physical stress caused by NMS.

Disturbance of the 5-hydroxytryptamine metabolism in brains from patients with Alzheimer's dementia

The 5-hydroxytryptamine (5-HT) system in the human brain is sensitive to aging. In dementia of the Alzheimer type (AD/SDAT), there are significantly reduced concentrations of 5-HT and 5-hydroxyindoleacetic acid (5-HIAA). 5-HT-sensitive imipramine binding is reduced by almost 50%, indicating a loss of presynaptic 5-HT terminals. There also seems to be reduced tryptophan hydroxylase activity in some brain areas. In cerebrospinal fluid (CSF) from AD/SDAT patients, the concentration of 5-HIAA is reduced, and the accumulation of 5-HIAA after probenecid loading is diminished. Biochemical findings together with structural findings in the raphe nuclei indicate that the disturbance of the 5-HT system is of the same magnitude as the disturbance of the cholinergic system. Reduced activity in the 5-HT system may be of importance for activity in the hypothalamus. There is an increased concentration of arginine vasopressin, which may explain the increased activity in the hypothalamic-pituitary-adrenal axis seen in patients with AD/SDAT. This activity is reduced when a selective 5-HT reuptake blocker is given. Pharmacological treatment with 5-HT reuptake blockers improves emotional disturbances, confusion, anxiety and depressed mood in patients with AD/SDAT.

Serotonin concentrations and turnover in brains of depressed suicides

5-Hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) concentrations and 5-HT turnover (5-HIAA/5-HT) were determined in 6 brain regions from 19 suicide victims in whom a retrospective diagnosis of depression was established, and 19 age- and sex-matched control subjects. Thirteen of the suicides were free of psychoactive drugs at the time of death; 5 were receiving antidepressant drugs. 5-HT, 5-HIAA and 5-HT turnover did not differ significantly between the total, drug-free and antidepressant-treated suicides and controls in frontal and temporal cortex, caudate and hippocampus. 5-HIAA concentration was significantly higher in amygdala of drug-free suicides than controls, whereas 5-HT and 5-HT turnover did not differ. 5-HT concentration was significantly lower in putamen of the total and antidepressant-treated suicides and a similar reduction was also apparent in the drug-free suicides. 5-HT turnover in putamen was significantly higher in the total and drug-free suicides compared to controls. 5-HT and 5-HIAA concentrations in putamen were significantly lower in drug-free suicides who died by non-violent means than in those who died by violent means. Differences between controls and suicides could not be attributed to age, sex or postmortem delay. These results offer no support for the view that 5-HT turnover is reduced in depressed subjects who commit suicide.

Evidence for a decline with age in behavioral responsivity to the serotonin agonist, m-chlorophenylpiperazine, in healthy human subjects

The functional significance of alterations in brain serotonin (5HT) associated with normal aging in both animals and humans is largely unknown. Using the effects of the 5HT agonist, m-chlorophenylpiperazine (m-CPP), as a measure of central serotonergic responsivity, we compared the behavioral and neuroendocrine responses of older normal volunteers (mean age +/- SD = 62.4 +/- 4.12) to those of younger normal volunteers (mean age +/- SD = 31.6 +/- 5.52). When m-CPP was administered intravenously, older subjects showed decreased behavioral responses but similar neuroendocrine responses, compared to younger subjects. The decreased behavioral responsivity was unrelated to pharmaco-kinetic differences between the groups, since m-CPP plasma levels were similar in both groups. This report is the first in vivo study in humans to demonstrate decreased behavioral responsivity with age following serotonergic stimulation, and may indicate a functionally less responsive 5HT subsystem in older subjects.

Biogenic amines and their metabolites in body fluids of normal, psychiatric and neurological subjects

The biogenic monoamines and their metabolites have been isolated, identified and quantified in human body fluids over the past forty years using a wide variety of chromatographic separation and detection techniques. This review summarizes the results of those studies on normal, psychiatric and neurological subjects. Tables of normal values and the methods used to obtain them should prove to be useful as a reference source for benchmark amine and metabolite concentrations and for successful analytical procedures for their chromatographic separation, detection and quantification. Summaries of the often contradictory results of the application of these methods to psychiatric and neurological problems are presented and may assist in the assessment of the validity of the results of experiments in this field. Finally, the individual, environmental and the methodological factors affecting the concentrations of the amines and their metabolites are discussed.

Neuroendocrine and behavioral effects of dietary tryptophan restriction in healthy subjects

The neuroendocrine and behavioral effects of gradual dietary tryptophan (TRP) depletion, utilizing two magnitudes of a 10-day TRP-restriction diet (700 mg/day and 200 mg/day), were studied in 22 healthy subjects. The prolactin response to a 7 gm L-TRP infusion was measured prior to and on day 10 of the diet. Both diets significantly reduced fasting total plasma TRP by 15 to 20%, but only the 200 mg/day TRP diet led to an enhancement of the prolactin response to intravenous L-TRP. Female subjects demonstrated a more robust increase in plasma prolactin following L-TRP infusion pre-diet and exhibited a larger decrease in plasma TRP following dietary TRP restriction compared to males. There were no significant behavioral effects of either diet. Gradual dietary TRP depletion leads to an enhancement of the prolactin response to L-TRP infusion, suggestive of postsynaptic serotonin receptor supersensitivity.

Analysis of equine cisterna magna cerebrospinal fluid for the presence of some monoamine neurotransmitters and transmitter metabolites

Small volumes (0.05 ml) of cisterna magna cerebrospinal fluid (CSF) from 23 neurologically normal horses were analysed for the monoamine neurotransmitters dopamine, norepinephrine, epinephrine, serotonin and their metabolites using high pressure liquid chromatography and electrochemical detection. Two metabolites, homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were present in all CSF samples. The deaminated and methylated metabolite of dopamine, HVA, was present at a mean concentration of 42.33 +/- 3.14 ng/ml of CSF. The deaminated metabolite of serotonin, 5-HIAA, was present at a mean concentration of 45.52 +/- 3.65 ng/ml of CSF. A positive correlation was found between the CSF concentrations of HVA and 5-HIAA (r = 0.72, p = 0.0003). The mean ratio of HVA to 5-HIAA concentrations was 1.07 +/- 0.05. The ratios of HVA to 5-HIAA concentrations were found to be more indicative of the serotonergic metabolite 5-HIAA (r = -0.62, p = 0.0016) than the dopaminergic metabolite HVA (r = 0.11, p = 0.60). There was a stronger relationship between the concentrations of 5-HIAA and the ratios of HVA to 5-HIAA in male CSF (r = -0.85, p = 0.0006) than in female CSF (r = -0.54, p = 0.01). Concentrations of CSF neurotransmitter metabolites were evaluated in horses grouped by age (0-4, 5-9 and 10-13 years). The youngest group of horses had a significantly (p = 0.003) greater CSF concentration of HVA than of 5-HIAA. The 10-13-year-old horses had a significantly (p = 0.02) lower mean CSF HVA concentration than the 0-4-year-old horses. No age-related differences in CSF 5-HIAA concentrations were detected.

Alterations in hypothalamic serotonergic-catecholaminergic relationships in aging C57BL/6J female mice

The effects of aging and estradiol on the three major hypothalamic monoaminergic systems were measured in female C57BL/6J mice. Both aging and estradiol treatment induced small (10-15%) changes in the levels and ratios of the monoamines and their catabolites. In addition, the levels of 5-hydroxyindoleacetic acid, the major serotonergic catabolite, were strongly correlated with the levels of the two major dopaminergic catabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid. Aging affected the relationship between 5-hydroxyindoleacetic acid and the dopaminergic catabolites such that the slope of the regression lines of 5-hydroxyindoleacetic acid on the dopaminergic compounds was increased in older mice. The age-related alteration in the correlations between the serotonergic and dopaminergic compounds may be due to an effect of aging on the acid export system.

Tetrahydrobiopterin and biogenic amine metabolism in neuropsychiatry, immunology, and aging

Tetrahydrobiopterin (BH4) is essential for biogenic amine synthesis, and alterations in its metabolism occur at birth (atypical PKU), in neuropsychiatric illnesses, and in aging. BH4 therapy has been attempted in atypical PKU and in neuropsychiatric illness with some success and may become more viable as more is learned about BH4 metabolism and ways are discovered to elevate brain BH4 levels. It is intriguing to consider that a genetic defect in BH4 biosynthesis occurring at birth might go unrecognized and contribute to altered biogenic amine metabolism that occurs in neuropsychiatric illness. Since there seems to be a sensitivity of BH4 metabolism to genetic alterations, it is possible that altered BH4 metabolism is involved in some of deleterious effects associated with the aging process. A link between genetic alterations in BH4 metabolism at birth and adult neuropsychiatric illness and aging remains to be established, although this seems plausible. The presence of BH4 and other pterins in cells of the immune system as well as the pineal gland and other neuroendocrine tissues suggests the potential for other functions of pterins. Hopefully, future research will uncover the full potential for the therapeutic use of BH4 in a variety of diseases as well as elucidating other potential roles for pterin molecules which are present in many different systems.

Changes in the aging brain as they affect psychotropics: a review

This article reviews a number of neuroanatomic and neurochemical changes that occur in the brain with aging, and focuses specifically on those that may affect the response to psychotropic drugs. We hope to increase physicians' awareness of these "central," or brain, changes, that occur with aging when prescribing and monitoring psychotropic use, since the traditional emphasis in prescribing for the elderly has rested with the review of pharmacokinetic, or "peripheral" organ changes.

The neurobiology of aging: does it predispose to depression?

This review examines the various research approaches undertaken to investigate possible central nervous system correlates of major depressive illness and relates findings from these studies to the alterations in central nervous system and neuroendocrine function that normally accompany aging in humans. The topics reviewed include: epidemiology of depression and suicide in the elderly; monoamine theories of depression; neuroendocrine disturbances in depression; and imaging studies.

Pre-menopausal and post-menopausal depressed women

In a consecutive series of 28 depressed women, pre-menopausal (n = 13) and post-menopausal (n = 15) patients were compared. Post-menopausal women had significantly higher levels of plasma norepinephrine, plasma 3-methoxy-4-hydroxyphenylglycol, post-dexamethasone plasma cortisol, cerebrospinal fluid 3-methoxy-4-hydroxyphenylglycol and corticotropin-releasing hormone. However, when biologic measures were adjusted for age by analyses of covariance there were no significant differences. Pre-menopausal women had had significantly more life events before the onset of depression than post-menopausal women. The implications of these findings are discussed.

Different neurotransmitter metabolite concentrations in CSF samples from inpatient and outpatient normal volunteers

Cerebrospinal fluid concentrations of the neurotransmitter metabolites 5-hydroxyindoleacetic acid (5HIAA), homovanillic acid (HVA), 3,4-dihydroxyphenylacetic acid (DOPAC) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were compared in two groups of healthy volunteer subjects. One group (outpatient) was composed of 27 subjects who were transported to the outpatient clinic on the day of the lumbar puncture (LP). The other group (inpatient) was composed of 10 subjects who were admitted to the NIMH Research Ward on the evening prior to the LP. After statistical adjustment for age, height, sex and season in which LP was performed the inpatient group had significantly higher concentrations of both 5HIAA and HVA (P less than 0.005 and P less than 0.05, respectively) than the outpatient group. The difference in DOPAC concentration approached significance (P = 0.056), but there was no difference in MHPG concentration between the groups. This result indicates the need for strict control of environment in studies of CSF monoamines and their metabolites.

Interacting neurotransmitter systems. A non-experimental approach to the 5HIAA-HVA correlation in human CSF

The repeatedly observed strong positive correlation between 5-hydroxyindoleacetic acid (5HIAA) and homovanillic acid (HVA) in human cerebrospinal fluid (CSF) prompted an investigation to see if conclusions concerning possible interactions between brain serotonin and dopamine turnover could be reached from human CSF concentrations of these acid metabolites. CSF data from patients with depressive disorders diagnosed according to the RDC from Sweden (n = 140) and from the National Institute of Mental Health (n = 35) were used to test structural hypotheses by two statistical approaches--LISREL analysis and logistic regression. Results from both men and women were unequivocal: 5HIAA "controls" HVA, interpretable as a regulatory action of serotonin turnover on dopamine turnover. In women, only 5HIAA was affected by age, height and body size (higher in elderly, short and stout women); no similar relationships were seen in males. The concept of a serotonergic regulation of dopamine turnover was tested on brain punch analyses of serotonin and dopamine and their metabolites in two sets of dogs in a large number of brain areas. Results confirm a facilatory effect of serotonin on indices of dopamine turnover in many brain regions, especially brain stem and hypothalamus. The animal data validate the data analytic approach in humans.

Cerebrospinal fluid monoamine precursor and metabolite levels in children treated for leukemia: age and sex effects and individual variability

Lumbar cerebrospinal fluid (CSF) was obtained from children during and following treatment for acute lymphoblastic leukemia (ALL). One hundred ninety-two CSF samples from 50 subjects, which were selected to minimize the effects of the disease and its treatment (i.e., to approach "normality" as closely as possible), were analyzed for the monoamine precursors tyrosine (Tyr) and tryptophan (Trp) and the metabolites homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA). Levels of HVA (p less than 0.0001), 5-HIAA (p less than 0.002), and Tyr (p less than 0.05) decreased with age from 3 to 17 years. Significant correlations were observed between the acid metabolites HVA and 5-HIAA (r = 0.79) and between the amino acid precursors Tyr and Trp (r = 0.71). Within individuals, levels of all four compounds were relatively stable over time, with total mean coefficient of variation ranging from 20% to 25%. No significant sex differences for CSF levels of HVA, 5-HIAA, Tyr, or Trp were found. Assessment of CSF monoamine precursors and metabolites in children treated for ALL may provide a method for understanding the chronic effect of CNS trauma on the ontogeny of monoamine systems.

Low HVA and normal 5HIAA CSF levels in drug-free schizophrenic patients compared to healthy volunteers: correlations to symptomatology and family history

Cerebrospinal fluid (CSF) levels of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5HIAA) were determined in 40 drug-free schizophrenic patients and 21 healthy volunteers by a mass fragmentographic method. Twenty-one of the schizophrenic patients were first admissions who had never received neuroleptics. Significantly, lower levels of HVA but not 5HIAA were found in the patient group, and no difference was found between chronic, previously neuroleptic-treated and never-medicated patients. HVA levels correlated positively with social interest and total positive scores on the Nurses Observation Scale for Inpatient Evaluation (NOSIE-30) and negatively with lassitude and slowness of movements on the Comprehensive Psychopathological Rating Scale (CPRS). Low levels of 5HIAA were correlated to the CPRS items delusions and apparent sadness. There were slightly higher CSF levels of 5HIAA in patients with a family history of schizophrenia, but no such difference was seen for HVA. In both schizophrenic and control subjects CSF levels of HVA and 5HIAA showed a strong intraindividual correlation. The results indicate decreased central nervous system dopaminergic turnover in schizophrenia which seems to be associated with "negative" symptomatology.

Neurotransmitter precursors and metabolites in CSF of human neonates

The amino-acid precursors tryptophan and tyrosine, and the major metabolites 5-hydroxyindoleacetic acid, indoleacetic acid, homovanillic acid and 3-methoxy-4-hydroxyphenethyleneglycol, related to the central neurotransmitters serotonin, dopamine and norepinephrine, were measured in 62 samples of cerebrospinal fluid from human neonates. Means are reported for the samples from 17 medically uncomplicated infants and for the larger group (42 to 45) of infants with medical complications. The latter group was divided according to diagnosis and medication. All groups had significantly higher levels of all compounds in comparison with older children and adults. There were few significant subgroup differences in the group with complications. In both the normal and complicated groups a number of significant correlations were observed between the compounds themselves and with other physiological measures.