3-Methoxy-4-hydroxyphenethyleneglycol production by human brain in vivo

Association of working memory and elevated overnight urinary norepinephrine in patients with schizophrenia

INTRODUCTION

Norepinephrine has both central and peripheral origins and is known to influence cognitive processes in attention, learning, and working memory, but the research regarding the impact of norepinephrine on cognition in schizophrenia remains sparse, and mainly focuses on centrally regulated noradrenergic effects. This study examined the relationship between cumulative overnight norepinephrine levels in the urine and working memory in patients with schizophrenia and healthy controls.

METHODS

Urinary catecholamines were collected overnight in patients with schizophrenia (n = 75) and healthy controls (n = 33). Working memory was assessed using the digit sequencing task.

RESULTS

Patients showed significantly higher average levels of overnight norepinephrine (t(103.10) = -3.16, p = 0.002) and reduced working memory performance (t(90) = 3.87, p = 0.001) compared with healthy individuals. There was a significant negative correlation between norepinephrine and working memory in patients (r = -0.38, p = 0.005), but not in controls (r = 0.08, p = 0.67). After controlling for age, sex, antipsychotic medications, and serotonin-norepinephrine reuptake inhibitor-based antidepressants, the correlation remained significant (r = -0.41, p = 0.004).

CONCLUSIONS

High peripheral overnight levels of urinary norepinephrine are associated with lower working memory performance in patients with schizophrenia. These results parallel previous studies suggesting that high levels of central norepinephrine may result in working memory impairments. As norepinephrine rapidly breaks down and usually does not pass through the blood-brain barrier, the potential effect of peripheral cumulative norepinephrine on working memory is intriguing, and needs to be further investigated.

Plasma monoamines change under dopamine supersensitivity psychosis in patients with schizophrenia: A comparison with first-episode psychosis

BACKGROUND

Patients with first-episode psychosis respond well to initial antipsychotic treatment, but among patients experiencing a relapse of psychosis, the response rate falls to approximately 30%. The mechanism of this discrepancy has not been clarified, but the development of dopamine supersensitivity psychosis with the underlying up-regulation of post-synaptic dopamine D2 receptors could be involved in this lesser response. It is uncertain whether elevated dopamine synthesis and release occurs in patients with dopamine supersensitivity psychosis, in contrast to those with first-episode psychosis.

PATIENTS AND METHODS

We examined a first-episode psychosis group (n=6) and a chronic schizophrenia group, i.e. patients experiencing relapse (n=23) including those who relapsed due to dopamine supersensitivity psychosis (n=18). Following the initiation of treatment, we measured the patients' blood concentrations of homovanillic acid and 3-methoxy-4-hydroxyphenylglycol at two weeks and four weeks after the baseline measurements.

RESULTS

The first-episode psychosis group tended to show decreased homovanillic acid, accompanied by an improvement of symptoms. The chronic schizophrenia group showed no alteration of homovanillic acid or 3-methoxy-4-hydroxyphenylglycol over the treatment period. These results were the same in the dopamine supersensitivity psychosis patients alone.

CONCLUSIONS

Our findings suggest that unlike first-episode psychosis, the release of dopamine from presynaptic neurons did not increase in relapse episodes in the patients with dopamine supersensitivity psychosis. This indirectly indicates that the development of supersensitivity of post-synapse dopamine D2 receptor is involved in relapse in dopamine supersensitivity psychosis patients.

Attention-Deficit Hyperactivity Disorder

Attention-deficit hyperactivity disorder (ADHD) is the most common of the childhood psychiatric disorders, with a prevalence rate of up to 20%, and is probably genetically transmitted. ADHD is characterized by impulsive behavior, hyperactivity, and decreased attention span. It is often extremely disruptive to the afflicted individuals social interactions and school performance. Therapeutic approaches to ADHD should be multimodal, including medications, family, and educational therapies. The pathophysiology of ADHD is not yet fully understood. Catecholoamines are believed to play a significant role with serotonin in an adjunctive role. Pathophysiological theories are supported by useful drug therapies that are known to affect dopamine and norepinephrine metabolism. Stimulants remain the drugs of choice, with methylphenidate most commonly used. Dextroamphetamine and pemoline are also effective. The rational use of these drugs is discussed. Antidepressants are second-line drug therapies; their usefulness is most apparent in patients who have high levels of anxiety and/or depression. Other potentially useful medications, including clonidine and the antipsychotics, are discussed. Adult populations can also express ADHD; treatment is similar to that used in children. Overall, ADHD is an important illness with significant morbidity. Pharmacotherapy is highly effective for its treatment and forms the cornerstone of therapy. This review of ADHD seeks to promote a greater understanding of this disorder and its appropriate drug therapy.

Norepinephrine and impulsivity: effects of acute yohimbine

RATIONALE

Rapid-response impulsivity, characterized by inability to withhold response to a stimulus until it is adequately appraised, is associated with risky behavior and may be increased in a state-dependent manner by norepinephrine.

OBJECTIVE

We assessed effects of yohimbine, which increases norepinephrine release by blocking alpha-2 noradrenergic receptors, on plasma catecholamine metabolites, blood pressure, subjective symptoms, and laboratory-measured rapid-response impulsivity.

METHODS

Subjects were 23 healthy controls recruited from the community, with normal physical examination and ECG, and negative history for hypertension, cardiovascular illness, and axis I or II disorder. Blood pressure, pulse, and behavioral measures were obtained before and periodically after 0.4 mg/kg oral yohimbine or placebo in a randomized, counterbalanced design. Metabolites of norepinephrine [3-methoxy-4-hydroxyphenylglycol (MHPG) and vanillylmandelic acid (VMA)] and dopamine [homovanillic acid (HVA)] were measured by high-pressure liquid chromatography with electrochemical detection. Rapid-response impulsivity was measured by commission errors and reaction times on the immediate memory task (IMT), a continuous performance test designed to measure impulsivity and attention.

RESULTS

Yohimbine increased plasma MHPG and VMA but not HVA. Yohimbine increased systolic and diastolic blood pressure and pulse rate. On the IMT, yohimbine increased impulsive errors and impulsive response bias and accelerated reaction times. Yohimbine-associated increase in plasma MHPG correlated with increased impulsive response rates. Time courses varied; effects on blood pressure generally preceded those on metabolites and test performance.

CONCLUSIONS

These effects are consistent with increased rapid-response impulsivity after pharmacological noradrenergic stimulation in healthy controls. Labile noradrenergic responses, or increased sensitivity to norepinephrine, may increase risk for impulsive behavior.

Relationships between stress, social adaptation, personality traits, brain-derived neurotrophic factor and 3-methoxy-4-hydroxyphenylglycol plasma concentrations in employees at a publishing company in Japan

There is growing evidence that blood levels of brain-derived neurotrophic factor (BDNF) and 3-methoxy-4-hydroxyphenylglycol (MHPG), a major metabolite of noradrenaline, are related to depression-associated personality traits as well as to depressive, suicidal and anxious states. Psychological job stress is well known to lead to symptoms of depression, anxiety and suicide. We have recently reported that psychological job stress among hospital employees altered blood levels of BDNF and MHPG (Mitoma et al., 2008). In the present study, we re-examined the effects of social adaptation and personality traits, as well as those of psychological job stress, on plasma levels of BDNF and MHPG in healthy employees (n=269, male/female=210/59, age=49 ± 10years) working in a publishing company in Japan. The values (mean ± SD) of scores on the Stress and Arousal Check Lists (s-SACL and a-SACL), Social Adaptation Self-evaluation Scale (SASS), plasma MHPG levels and plasma BDNF levels were 6.0 ± 3.4, 5.7 ± 2.3, 33.7 ± 6.8, 5.8 ± 4.3 and 4.6 ± 3.1ngml(-1), respectively. A positive correlation was found between plasma MHPG levels and scores on the s-SACL, but not the a-SACL. A positive correlation was also found between SASS scores and plasma MHPG levels and between SASS scores and plasma BDNF levels. A negative correlation was found between plasma BDNF levels and s-SACL scores. Furthermore, a positive correlation between NEO-Five factor Inventory (Openness) scores and plasma MHPG levels was observed, as well as between NEO-Five factor Inventory (Extroversion) scores and plasma BDNF levels. These results suggest that levels of plasma BDNF and plasma MHPG might be associated with psychological job stress and certain personality traits among employees in the publishing industry in Japan.

Different patterns of longitudinal changes in plasma levels of catecholamine metabolites and brain-derived neurotrophic factor after administration of atypical antipsychotics in first episode untreated schizophrenic patients

In the present study, we longitudinally investigated the effects of risperidone, olanzapine, and aripiprazole on plasma levels of catecholamine metabolites and brain-derived neurotrophic factor (BDNF) in first-episode unmedicated schizophrenic patients. The subjects were 59 Japanese schizophrenic patients (35 males and 24 females; age range: 18-46 years; mean+/-SD: 25+/-16 years). The patients were treated with risperidone (n=32) in a dose range of 2-6 mg/day (mean+/-SD=3.4+/-1.9), olanzapine (n=18) in a dose range of 5-20 mg/day (mean+/-SD=12.1+/-5.8), or aripiprazole (n=9) in a dose range of 12-30 mg/day (mean+/-SD=22.8+/-10.1). All three drugs significantly decreased plasma homovanillic acid (HVA) levels within 8 weeks, although aripiprazole transiently raised this level before 8 weeks. All three drugs also significantly increased plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels within 8 weeks. On the other hand, none of them altered plasma BDNF levels. These results indicate that risperidone, olanzapine, and aripiprazole affect catecholaminergic systems in the brain, that the effects of aripiprazole on the dopaminergic systems seem to slightly different than those of risperidone and olanzapine, and that these atypical antipsychotic drugs might not alter BDNF levels, at least within 8 weeks of treatment.

Effects of acute paroxetine treatment on the consumption of cigarette smoking and caffeine in depressed patients

In the present study, we examined the effects of acute treatment with paroxetine on the consumption of cigarette smoking and caffeine in 65 patients who met the DSM-IV criteria for major depressive disorder (M/F: 28/37, age: 48 +/- 15 years). Plasma levels of cotinine or caffeine were analysed using high-performance liquid chromatography (HPLC). The amount of cigarette smoking and plasma levels of cotinine, but not caffeine, decreased 4 weeks after paroxetine treatment. There was no difference between smokers and nonsmokers with respect to their response to paroxetine treatment. In addition, plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) levels in responders to paroxetine treatment was higher than those in nonresponders, and there was a negative correlation between the changes in plasma MHPG levels and the changes in Hamilton rating scale for depression (Ham-D) scores before and 4 weeks after paroxetine administration. These results suggest that paroxetine has the potential to reduce the amount of cigarette smoking in depressed smokers, and we reconfirmed our previous results that depressed patients with higher plasma MHPG levels had better response to paroxetine treatment than those with lower plasma MHPG levels using larger depressed samples.

Increased brain serotonin turnover in panic disorder patients in the absence of a panic attack: reduction by a selective serotonin reuptake inhibitor

Since the brain neurotransmitter changes characterising panic disorder remain uncertain, we quantified brain noradrenaline and serotonin turnover in patients with panic disorder, in the absence of a panic attack. Thirty-four untreated patients with panic disorder and 24 matched healthy volunteers were studied. A novel method utilising internal jugular venous sampling, with thermodilution measurement of jugular blood flow, was used to directly quantify brain monoamine turnover, by measuring the overflow of noradrenaline and serotonin metabolites from the brain. Radiographic depiction of brain venous sinuses allowed differential venous sampling from cortical and subcortical regions. The relation of brain serotonin turnover to serotonin transporter genotype and panic disorder severity were evaluated, and the influence of an SSRI drug, citalopram, on serotonin turnover investigated. Brain noradrenaline turnover in panic disorder patients was similar to that in healthy subjects. In contrast, brain serotonin turnover, estimated from jugular venous overflow of the metabolite, 5-hydroxyindole acetic acid, was increased approximately 4-fold in subcortical brain regions and in the cerebral cortex (P < 0.01). Serotonin turnover was highest in patients with the most severe disease, was unrelated to serotonin transporter genotype, and was reduced by citalopram (P < 0.01). Normal brain noradrenaline turnover in panic disorder patients argues against primary importance of the locus coeruleus in this condition. The marked increase in serotonin turnover, in the absence of a panic attack, possibly represents an important underlying neurotransmitter substrate for the disorder, although this point remains uncertain. Support for this interpretation comes from the direct relationship which existed between serotonin turnover and illness severity, and the finding that SSRI administration reduced serotonin turnover. Serotonin transporter genotyping suggested that increased whole brain serotonin turnover most likely derived not from impaired serotonin reuptake, but from increased firing in serotonergic midbrain raphe neurons projecting to both subcortical brain regions and the cerebral cortex.

Catecholamine metabolism: a contemporary view with implications for physiology and medicine

This article provides an update about catecholamine metabolism, with emphasis on correcting common misconceptions relevant to catecholamine systems in health and disease. Importantly, most metabolism of catecholamines takes place within the same cells where the amines are synthesized. This mainly occurs secondary to leakage of catecholamines from vesicular stores into the cytoplasm. These stores exist in a highly dynamic equilibrium, with passive outward leakage counterbalanced by inward active transport controlled by vesicular monoamine transporters. In catecholaminergic neurons, the presence of monoamine oxidase leads to formation of reactive catecholaldehydes. Production of these toxic aldehydes depends on the dynamics of vesicular-axoplasmic monoamine exchange and enzyme-catalyzed conversion to nontoxic acids or alcohols. In sympathetic nerves, the aldehyde produced from norepinephrine is converted to 3,4-dihydroxyphenylglycol, not 3,4-dihydroxymandelic acid. Subsequent extraneuronal O-methylation consequently leads to production of 3-methoxy-4-hydroxyphenylglycol, not vanillylmandelic acid. Vanillylmandelic acid is instead formed in the liver by oxidation of 3-methoxy-4-hydroxyphenylglycol catalyzed by alcohol and aldehyde dehydrogenases. Compared to intraneuronal deamination, extraneuronal O-methylation of norepinephrine and epinephrine to metanephrines represent minor pathways of metabolism. The single largest source of metanephrines is the adrenal medulla. Similarly, pheochromocytoma tumor cells produce large amounts of metanephrines from catecholamines leaking from stores. Thus, these metabolites are particularly useful for detecting pheochromocytomas. The large contribution of intraneuronal deamination to catecholamine turnover, and dependence of this on the vesicular-axoplasmic monoamine exchange process, helps explain how synthesis, release, metabolism, turnover, and stores of catecholamines are regulated in a coordinated fashion during stress and in disease states.

Clinical response to antidepressant treatment and 3-methoxy-4-hydroxyphenylglycol levels: mini review

Plasma 3-methoxy-4-hydroxyphenylglycol (MHPG) may provide valuable information regarding central noradrenergic activity. In this article, we mainly reviewed about the associations between plasma MHPG levels and responses to antidepressant treatment. There exists heterogeneity of depression with regards to plasma levels of MHPG; in other words, depressed patients might be dichotomized into one group characterized by anxiety and/or perceptions of powerlessness with high plasma MHPG levels and another group characterized by psychomotor retardation with low plasma MHPG levels. In addition, it is possible that patients with lower pretreatment MHPG levels might respond to drugs that affect both noradrenergic neurons and serotonergic neurons or predominantly noradrenergic neurons. On the other hand, patients with higher pretreatment MHPG levels might respond to drugs that affect predominantly serotonergic neurons or GABAergic neurons. It is possible to predict the responses to antidepressant drugs by means of plasma MHPG levels in depressed patients.

The urinary MHPG/creatinine ratio and its relationship to platelet monoamine oxidase activity in abstinent alcoholics

This study was designed to assess the baseline noradrenergic turnover of subgroups of postwithdrawal abstinent alcoholics and healthy controls. The method chosen was an overnight fasting urine sample of the breakdown product of norepinephrine, MHPG, related to urinary creatinine. A comparison was made with platelet monoamine oxidase activity and also within subgroups of the study population. This study found no difference between alcoholics and controls, nor between subgroups of postwithdrawal alcoholics in their level of urinary MHPG corrected for creatinine, and no significant correlation with major subject characteristics or with platelet monoamine oxidase. There was a trend, however, towards a significant correlation with duration of abstinence from alcohol, and there was a correlation with a history of fighting when drinking alcohol, but not with sociopathic traits overall. Within the type 2 alcoholics there was a significant correlation with a history of fighting when drinking and a negative correlation with behavioral tolerance to alcohol. It is possible that only the subset of type 2 alcoholics with certain antisocial characteristics have noradrenergic abnormalities. Although no statistical difference was found between the different groups under study, the information is helpful in increasing understanding of the noradrenergic system in abstinent alcoholics.

A simplified routine assay for urinary 3-methoxy-4-hydroxyphenylglycol

Urinary 3-methoxy-4-hydroxyphenylglycol (MHPG) level may provide us with a biochemical index for central noradrenergic activity. Previous methods for assaying MHPG in urine often lacked specificity, sensitivity, cost-effectiveness or convenience. We now describe a simplified routine assay for urinary MHPG by high-pressure liquid chromatography using electrochemical detection. For convenience and cost-effectiveness within a typical batch assay of total MHPG, 0.5 mL of urine sample, 50 microL of glusulase and 4 micrograms iso-vanillyl alcohol (internal standard) were used to hydrolyze conjugated MHPG at 37 degrees C overnight. Alternatively, for a same-day operation, it is efficient to hydrolyze the sample at 50 degrees C for 3 hours. Each sample was separated isocratically on a reversed-phase column (Ultracarb 5 ODS) at 25 degrees C with the flow rate at 1 mL/min. Intra- and inter-assay coefficients of variation were found to be 4.0% (n = 10) and 5.0% (n = 27), respectively, for MHPG at a mean concentration of 1.9 mg/L. Sulfatase or glucuronidase can be substituted for glusulase to obtain either sulfate- or glucuronide-conjugated MHPG. This procedure requires smaller sample amounts and less preparation time without compromising sensitivity and reproducibility.

The relationship between plasma MHPG and NE: employing regression models in estimating centrally derived MHPG and peripheral NE turnover rate in panic disorder

Studies investigating the role of the noradrenergic system in the pathophysiology of anxiety have focused on measuring plasma 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) levels. Fewer studies have examined norepinephrine levels. Basal plasma norepinephrine and free MHPG levels were simultaneously measured in 33 normal controls and 20 panic disorder (PD) patients. Norepinephrine levels were similar in patients and controls, but MHPG levels were significantly lower in patients (13.34 +/- 3.22 vs 18.37 +/- 4.49 pmol ml-1, p < 0.0001). Norepinephrine correlated significantly with plasma MHPG levels in controls (r = 0.538, p < 0.0001) and patients (r = 0.645, p < 0.002). Patients had a trend toward a lower y-intercept than controls, suggesting a lower contribution by the CNS to MHPG pool plasma levels (9.18 vs 12.51, p < 0.08). Norepinephrine turnover rate was similar in patients and controls. We propose that the dysregulation in the noradrenergic system in PD may be akin to animal studies of acute-on-top-of-chronic stress paradigms, whereby chronic stress results in normal or decreased basal NE turnover and sensitized responses to recurrent stresses.

Chiral analysis of 3-methoxy-4-hydroxyphenylglycol in human urine

Since 3-methoxy-4-hydroxyphenylglycol (MHPG) is a neutral metabolite from norepinephrine, it will be a diagnostic marker for mental diseases such as depression. For the development of an immunoassay, the natural enantiomer of MHPG would be required to prepare its antigen and to examine the specificity of the antibody. A natural enantiomer synthesized, however, has not been obtained so far. In this paper, we attempted to enantioseparate synthetic DL-MHPG and to assign D-enantiomer from the optical rotation of MHPG purified from human urine, because endogenous norepinephrine occurs as D-enantiomer which should metabolically generate D-MHPG. Enantioseparation conditions were tested using a Ceramospher Chiral RU-1 column (4.6 x 250 mm) at a flow rate of 0.5 ml/min. The resolution was adequate for the analysis and purification of synthetic DL- and the urinary MHPGs using methanol as a mobile phase and the column temperature at 0 degrees C, where DL-MHPG was detected as two peaks. The earlier peak (peak 1) showed (-) optical rotation, while the latter gave (+) optical rotation. After being treated with beta-glucuronidase, the normal human urine was extracted with ethyl acetate and then evaporated to dryness. The residue was suspended in water and the supernatant was analyzed and purified by a reversed phase column with a multi channel detector. A peak corresponding to MHPG was collected and concentrated to dryness. The pooled residues were dissolved in methanol and enantioseparated on the chiral HPLC. The urinary MHPG appeared as a single peak which was corresponded to the earlier peak of DL-MHPG and showing (-) optical rotation. Thus, the urinary MHPG was found to be D-(-)-MHPG. Then the absolute configuration of enantioseparated MHPGs were assigned to each optical rotation, judging from the chemical data and the metabolic pathway of the urinary D-MHPG. These enantiomers will be useful for studying on biochemistry and immunoassay.

Plasma free 3-methoxy-4-hydroxyphenylglycol predicts response to fluoxetine

This study was designed to investigate the relationship between platelet serotonin (5-HT) and plasma free 3-methoxy-4-hydroxyphenylglycol (MHPG) measures in depressed outpatients obtained from the same patient with unipolar depression during the pretreatment period and subsequent response to 6 weeks of treatment with either fluoxetine or maprotiline. Compared to the nonresponder group, the fluoxetine responders showed significantly higher pretreatment levels of MHPG, but no difference in pretreatment 5-HT levels. There were no significant differences in either 5-HT or MHPG levels between maprotiline responders and nonresponders. As to posttreatment levels, there were no between-group differences in 5-HT or MHPG between responders and nonresponders to either fluoxetine or maprotiline. When the relationships between changes in 5-HT or MHPG levels and treatment response were examined, 5-HT values showed a marked decrease in both fluoxetine responders and nonresponders, but no significant changes were found in the maprotiline treatment groups. On the other hand, MHPG levels in the fluoxetine nonresponders tended to increase (borderline significance), whereas the MHPG levels for fluoxetine responders and maprotiline responders and nonresponders were unaffected from pre- to posttreatment. Pretreatment levels of plasma free MHPG appear to predict response to fluoxetine.

Regional origins of 3-methoxy-4-hydroxyphenylglycol in plasma: effects of chronic sympathetic nervous activation and denervation, and acute reflex sympathetic stimulation

The plasma level and urinary excretion of 3-methoxy-4-hydroxyphenylglycol (MHPG), the principal metabolite of noradrenaline in the brain, are often used as indicators of central nervous system noradrenergic activity. Using percutaneously placed catheters, we studied the regional inputs into the plasma MHPG pool in 62 healthy volunteers. Veno-arterial plasma concentration differences and regional organ blood flows were used to quantify the relative amounts of MHPG contributed by various sites into plasma. Positive veno-arterial concentration gradients were found across the forearm, cardiac and jugular vessels in the healthy subjects. By far the majority of MHPG in plasma was derived from skeletal muscle, 5.3 +/- 1.8 nmol/min, with only minimal contribution (0.9 +/- 0.2 nmol/min) from the brain. Thus, to obtain an accurate indication of central nervous system noradrenergic activity the confounding influences of regional MHPG production must be excluded. 34 patients with chronic congestive heart failure, 6 patients with pure autonomic failure and 9 recent heart transplant recipients were used to investigate the possible effects of chronic sympathetic nervous system overactivity and sympathetic underactivity and denervation on peripheral MHPG production and plasma MHPG concentration. To examine the utility of plasma MHPG determinations as an indicator of acute alterations in sympathetic nervous activity we examined the influence of a variety of laboratory stressors on the arterial level and cardiac production of MHPG. The resting arterial plasma MHPG concentration mirrored sympathetic function in the patients with cardiac failure (sympathetic activation) and pure autonomic failure (sympathetic denervation), with mean MHPG plasma concentrations being 180 and 40% of those in healthy subjects. Cardiac MHPG production was increased in heart failure patients, and near zero with the cardiac sympathetic denervation accompanying transplantation and pure autonomic failure. In contrast, acute reflex stimulation of sympathetic nervous activity was not associated with parallel changes in the arterial level or cardiac production of MHPG. Measurements of peripheral plasma MHPG levels provide an index of prevailing sympathetic nervous function in clinical models of sympathetic overactivity and denervation, but are insensitive to acute sympathetic nervous system responses.

Effects of tryptophan depletion on responses to yohimbine in healthy human subjects

There is considerable evidence that both the norepinephrine (NE) and serotonin (5-HT) systems are involved in the regulation of human anxiety and fear responses. To assess the modulating effects of central 5-HT levels on NE function, 11 healthy human subjects were studied with placebo-controlled challenge tests involving tryptophan depletion followed by administration of the alpha-2-adrenergic antagonist yohimbine 0.4 mg/kg IV. Five of the 11 subjects reported a marked increase in feelings of nervousness (> or = 25 mm on a 100 mm analog scale) following the combination test, while 1/11 had this response to yohimbine alone. No subjects had an increase in nervousness during other control tests. The increase in nervousness after the tryptophan depletion-yohimbine test was statistically significant for the whole group, but there were no other unique changes in behavioral, physiologic or biochemical (MHPG, cortisol) variables with this test. These data are discussed in terms of possible functional interactions between the 5-HT and NE neurotransmitter systems.

Central nervous system noradrenergic and dopaminergic turnover in response to acute neuroleptic challenge

The objective of this study was to obtain direct neurochemical measures of the central nervous system's response to a typical neuroleptic, haloperidol, in human subjects. Nine healthy volunteers participated in this study. Central nervous system neuronal activity was assessed by measuring the plasma concentration and overflow from the brain of dopamine, norepinephrine, and their lipophilic and acidic metabolites after acute intravenous administration of haloperidol. By combining bilateral internal jugular vein blood sampling with cerebral blood flow scans we were able to differentiate between cortical and subcortical responses to haloperidol. The central nervous system response to haloperidol administration displayed a degree of regional specificity. Dopamine release, estimated from the overflow of homovanillic and dihydroxyphenylacetic acids, was reduced in cortical but not subcortical brain regions. Norepinephrine turnover was increased in cortical and subcortical brain regions. The overflow of homovanillic acid from the brain into the internal jugular veins was not related quantitatively to the arterial plasma concentrations of the catecholamines examined, homovanillic and dihydroxyphenylacetic acids or prolactin. Measurements of catecholamines and their metabolites in arterial plasma gave little indication as to monoaminergic neuronal activity in the brain.

Rapid HPLC assay with coulometric detection for norepinephrine and 3-methoxy-4-hydroxyphenylglycol in the mouse brain

For the rapid assay of norepinephrine (NE) and its major metabolite, 3-methoxy-4-hydroxyphenylglycol (MHPG) in the mouse brain, we developed a simple method using isocratic HPLC with coulometric detection. This method permits NE and MHPG assay within 5 min in one chromatographic run. Within-run coefficients of variation for NE and MHPG in the working standard solution were 0.8% and 0.6% (n = 50), respectively. The detector responses were linear from 0.025 to 100 pmol for NE and from 0.05 to 100 pmol for MHPG in the working standard solution. Using this method, the NE and MHPG concentrations were measured in discrete brain areas of the mouse prior treatment with or without alpha-methyl-p-tyrosine or N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP4).

Disruption of circadian MHPG rhythmicity in major depression

Plasma concentrations of total (free plus conjugated) 3-methoxy-4-hydroxyphenylglycol (MHPG) were determined every 3 hr for a 24-hr period in 32 unipolar depressed patients, 11 bipolar depressed patients, and 12 healthy subjects. Each subject's circadian MHPG rhythmicity was modeled by a sinusoidal function. Temporal parameters were estimated by linear least squares regression with a fixed 24-hr period. The variabilities associated with estimates of circadian amplitude and acrophase were roughly twice as large in the patients compared to healthy subjects. Phase advances were associated most significantly with the agitated rather than the retarded subtype of depression, and with first episode depressions. Treatment with desipramine (n = 26) did not alter significantly any of the model parameters and had no effect on circadian variability in any patient group. The data overall support a dysregulation theory for depressive illness with phase advances representing one manifestation of such dysregulation.

Tricyclic antidepressant withdrawal syndrome

OBJECTIVE

To examine the evidence pointing to a withdrawal syndrome associated with the discontinuation of tricyclic antidepressants (TCAs).

DATA SOURCES

MEDLINE searches were conducted. References used in relevant articles were screened for additional published information.

STUDY SELECTION

Emphasis was placed on human trials and individual case reports.

DATA SYNTHESIS

Symptoms of gastrointestinal and somatic distress, sleep disturbance, and movement disorders and mania have been temporally linked to withdrawal of TCAs. Cholinergic and adrenergic overdrive after TCA discontinuation have been suggested as the proposed mechanism for this syndrome. Reported symptoms may be psychosomatic or related to underlying mental illness.

CONCLUSIONS

Clinicians should be aware that discontinuation of TCA therapy may produce a withdrawal syndrome in some patients.

Sleep disorders and anxiety as symptom profiles of sympathoadrenal system hyperactivity in major depression

Recently, it has been reported that major depression is accompanied by an increased sympathoadrenal system (SAS) activity. In order to study the psychopathological correlates of SAS activity in depression, the authors measured the 24 h urinary excretion of catecholamines (CA), i.e., noradrenaline (NE), adrenaline (E), dopamine (DA) and the NE/E metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG) in 80 unipolar depressed subjects. The excretion of these indices of SAS activity have been studied in relation to the depressive items of the Structured Clinical Interview for DSM-III (SCID) and the Hamilton Depression Rating Scale (HDRS). There were significant positive correlations between the SCID item sleep disorders and the HDRS item middle insomnia, on the one hand, and NE, E and DA excretion, on the other. The MHPG excretion in 24 h urine was significantly and negatively related to somatic anxiety and hypochondriasis. It is suggested that these intertwined relationships between increased CA turnover, sleep discontinuity and anxiety may reflect the occurrence of a hyperarousal state in some major depressives that may be regarded as a coping response to various putative noxious stimuli.

Urinary amines in adults with Tourette's syndrome

Urinary amines and their metabolites were examined in 32 adults who met DSM-III-R diagnostic criteria for Tourette's Syndrome. These patients were compared with a control group that was of similar age and sexual representation. Analyses revealed significantly lower levels of 3-methoxy-4-hydroxyphenylglycol and serotonin as well as the metabolites of several "trace" amines including indoleacetic acid and m- and p-hydroxyphenylacetic acid. These findings persisted when Tourette's Syndrome patients taking medications were eliminated from the analyses. These data are consistent with reports of neurotransmitter abnormalities in children with Tourette's Syndrome. The differences in several trace amine metabolites suggest that the pathophysiology in this disorder is complex and involves a number of neurotransmitter and neuromodulator systems.

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.

Atrial natriuretic factor and salt wasting after aneurysmal subarachnoid hemorrhage

BACKGROUND AND PURPOSE

The causes of volume depletion and hyponatremia after subarachnoid hemorrhage are not fully understood but may be in part due to natriuresis or "cerebral salt wasting." Because previous studies using infrequent hormone sampling have given inconsistent results, we determined if elevations in atrial natriuretic factor concentrations preceded negative sodium and fluid balances.

METHODS

We measured diurnal atrial natriuretic factor and vasopressin concentrations and sodium balance for 5 days in 14 consecutive patients after aneurysmal subarachnoid hemorrhage.

RESULTS

Plasma concentrations of atrial natriuretic factor on admission were elevated in subarachnoid hemorrhage patients (mean +/- SD 106 +/- 59 pg/ml) compared with acutely ill controls (39 +/- 30 pg/ml). In eight patients, high peak concentrations of atrial natriuretic factor, greater than 300 pg/ml or a twofold increase above baseline, were followed by natriuresis and a negative sodium balance. Three patients, two of whom became hyponatremic, developed cerebral infarcts after natriuresis. Vasopressin concentrations were slightly elevated just after hemorrhage but subsequently declined to normal values.

CONCLUSIONS

A markedly increased atrial natriuretic factor concentration precedes natriuresis in some patients and, with other abnormalities of water handling possibly including a relatively diminished vasopressin concentration, may cause volume depletion. Patients with natriuresis appear to be at increased risk for delayed cerebral infarction after subarachnoid hemorrhage.

Clinical and biochemical aspects of depressive disorders: II. Transmitter/receptor theories

The present document is the second of three parts in a review that focuses on recent data from clinical and animal research concerning the biochemical bases of depressive disorders, diagnosis, and treatment. Various receptor/transmitter theories of depressive disorders are discussed in this section. Specifically, data supporting noradrenergic, serotonergic, cholinergic, dopaminergic, GABAergic, and peptidergic theories, as well as interactions between noradrenergic and serotonergic, or cholinergic and catecholaminergic systems are presented. Problems with the data and future directions for research are also discussed. A previous publication, Part I of this review, dealt with the classification of depressive disorders and research techniques for studying the biochemical mechanisms of these disorders. A future publication, Part III of this review, discusses treatments for depression and some of the controversies in this field.

Influence of beta-blockade on circulating plasma levels of 3-methoxy-4-hydroxy phenylethylene glycol (MHPG) during exercise in moderate hypertension

1. The effect of exercise testing and beta-blockade on plasma norepinephrine (PNE), and secretion of its metabolite 3-methoxy-4-hydroxyphenylethylene glycol (MHPG), was assessed in 28 mild-to-moderate hypertensives before and after the administration of dilevalol, a new beta-blocker with beta 2-agonism. 2. This double blind, placebo-controlled study consisted of two successive submaximal exercise tests before and after the administration of a single oral dose of dilevalol (200 mg, 400 mg or 600 mg). Plasma norepinephrine levels were determined at rest, at 100 watts step of exercise and at maximal effort (Emax). 3. During the control test, mean PNE levels increased from 1.73 +/- 0.52 nmol/L (resting value) to 8.01 +/- 4.01 nmol/L at Emax (P less than 0.01) as MHPG levels increased from 11.18 +/- 1.33 nmol/L (rest) to 17.50 +/- 1.15 nmol/L (Emax, P less than 0.01). After dilevalol, PNE increased significantly as compared to controls (P less than 0.05), from 2.32 +/- 0.99 to 12.42 +/- 5.97 nmol/L (P less than 0.01). PNE and MHPG levels were correlated, both at rest and during exercise. PNE levels after beta-blockade were linearly related to the dose of beta-blocker administered. MHPG levels were unaltered by the administration of dilevalol, both before and after exercise. 4. The increase in MHPG that occurs during bicycle exercise is largely generated from an increase in central nervous system noradrenergic activity. While dilevalol increases the peripheral sympathetic nervous system, both at rest and during exercise (which is reflected by increases in PNE levels) the drug does not alter resting central nervous system noradrenergic activity nor amplify the increase in central noradrenergic activity that occurs during exercise.

Genetic and phenotypic heterogeneity of inherited spike-wave epilepsy: two mutant gene loci with independent cerebral excitability defects

Two recessive gene loci controlling cerebral excitability in the mouse (tg, chr 8 and stg, chr 15) share generalized neocortical spike-wave seizures as a common mutant phenotype. Although the primary molecular defects are unknown, homozygous tg mutants display a gene-linked hyperplasia of central noradrenergic axons originating in the locus ceruleus, and early selective lesions of these fibers correct the epileptic phenotype in the adult. In contrast, we find that stg homozygotes, despite a more severe seizure disorder, show no alterations in regional noradrenergic fiber innervation, and seizure frequency is unaffected by neonatal noradrenergic depletion. These mutations demonstrate that excessive synchronous neuronal discharges alone are insufficient to trigger abnormal growth of locus ceruleus fibers, and reveal the existence of two distinct intervening brain neuromodulatory mechanisms, norepinephrine (NE)-dependent and NE-independent, underlying the inheritance of this common pattern of epilepsy.

Phenylethylaminergic mechanisms in attention-deficit disorder

Urinary excretion (24-hr) of beta-phenylethylamine (PEA), phenylacetic acid (PAA), phenylalanine (Phe), and p-tyrosine (Tyr), and plasma levels of PAA, Phe, and Tyr were examined in 18 normal children and 26 children diagnosed as having attention-deficit hyperactivity disorder (ADHD). The results indicated that urinary excretion (expressed per g of creatinine) of free and total PEA was significantly lower in the ADHD patients, and plasma levels of Phe and Tyr were also decreased in the ADHD subjects compared with the normal controls.

Urinary excretion of metabolites of norepinephrine in Tourette's syndrome

Urinary excretion of the norepinephrine metabolites 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) and normetanephrine (NMR) was measured in Tourette's Syndrome (TS) patients and in control subjects matched for age and education. The 24-h excretion (expressed per gram of creatinine) of total MHPG and of free and total (free + conjugated) NME was significantly lower in TS patients than in the normal subjects.

Generalized anxiety disorder: some biochemical aspects

Fifty-one patients who met DSM-III criteria for generalized anxiety disorder, and who were recruited to participate in a drug outcome study, filled out a variety of rating scales and had blood samples drawn for plasma norepinephrine, epinephrine, and free 3-methoxy-4-hydroxyphenylglycol (MHPG) after a 20-min rest period. This group was compared to 15 normal controls who also had their blood drawn after a 20-min rest period. While the two groups were initially found to have significantly different levels of plasma free MHPG through the use of t tests, this finding was not confirmed by subsequent discriminant analysis.

Urinary amines in Tourette's syndrome patients with and without phenylethylamine abnormality

Previous data indicated a subgroup of Tourette's syndrome patients with a beta-phenylethylamine (PEA) level that was lower than all subjects in a control group matched for age and education. The current study compared the subgroups of Tourette's syndrome patients (n = 28) from the previous study with 20 control subjects in regard to other amines and metabolites. Patients with low levels of PEA were also found to have lower levels of 3-methoxy-4-hydroxy-phenylglycol, normetanephrine, serotonin, m-tyramine, and p-tyramine. There was also some evidence of dopaminergic abnormalities in the low-PEA subgroup. These data provide suggest a role of PEA in the pathophysiology of some patients with Tourette's syndrome. This effect may be mediated through other neurotransmitter systems.

Urinary MHPG sulfate as a marker of central norepinephrine metabolism: a commentary

Measurement of total (free + conjugated) 3 methoxy-4-hydroxyphenylglycol (MHPG) in urine has long been used to assess the metabolism of central norepinephrine (NE). However, available data indicate that total MHPG is not a sensitive marker because the portion of urinary MHPG which derives from brain NE is less than was previously assumed. Several arguments support the view that central MHPG excretion is best represented by the urinary MHPG sulfate fraction. Accordingly, a new strategy has been introduced in last years, involving the separate determination of sulfate and glucuronide conjugates of MHPG as respective markers of central and peripheral NE metabolism. Various biochemical and pharmacological data obtained in healthy subjects and in patients with mental diseases support this hypothesis.

Changes in 24-hour urinary excretion of MHPG after four continuous nights of REM sleep deprivation in human volunteers

Eight healthy volunteers were deprived of rapid eye movement (REM) sleep for 4 consecutive nights. Twenty-four-hour urine samples were collected to determine levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) during basal, REM sleep deprivation, and REM recovery conditions. A control experiment was carried out in four subjects who were awakened in non-REM sleep for 4 consecutive nights. Subjects deprived of REM sleep showed significant MHPG increases on night 4 of sleep deprivation. MHPG levels in the control condition decreased, but not significantly. When MHPG levels in both experimental and control conditions were compared in the same four subjects, a significant difference was observed, indicating an effect of the control condition. Increased MHPG levels were related to REM sleep reduction and to the time and number of awakenings. Our findings seem to support an inverse homeostatic relationship between norepinephrine metabolism and REM sleep.

Relationship between plasma and cerebrospinal fluid norepinephrine and dopamine metabolites in a nonhuman primate

Major and minor pathways of metabolism in the mammalian CNS result in the formation of 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) and normetanephrine (NMN) from norepinephrine (NE), and homovanillic acid (HVA) and 3-methoxytyramine (3-MT) from dopamine (DA), respectively. The correlational relationships between HVA and 3-MT and between MHPG and NMN in primate CSF and plasma have not been described. These relationships may help to elucidate the usefulness of CSF and plasma metabolites as indices of CNS NE and DA activity. In addition, because NMN is unlikely to cross the blood-brain barrier. CSF NMN concentrations would not be confounded by contributions from plasma, which is a major issue with CSF MHPG. We have obtained repeated samples of plasma and CSF from drug-naive male squirrel monkeys and have measured the concentrations of MHPG, HVA, NMN, and 3-MT to define their correlational relationships. For the NE metabolites, significant correlations were obtained for CSF MHPG and NMN (r = 0.806, p less than 0.001), plasma MHPG and CSF NMN (r = 0.753, p less than 0.001), and plasma and CSF MHPG (r = 0.776, p less than 0.001). These results suggest that CSF and plasma MHPG and CSF NMN may reflect gross changes in whole brain steady-state noradrenergic metabolism. Only a single significant relationship was demonstrated for the DA metabolites, with CSF 3-MT correlating with plasma HVA (r = 0.301, p less than 0.025). The results for the DA metabolites probably reflect regional differences in steady-state brain dopaminergic metabolism.

Catecholamine depletion produces irrepressible saccadic eye movements in normal humans

To determine the effect of catecholamine depletion on ocular motor pathways in humans, we studied the eye movements of 3 normal subjects who received the drug metyrosine (alpha-methylparatyrosine). This drug temporarily depleted dopamine and norepinephrine, as measured by a reduction in the metabolite, 3-methoxy-4-hydroxy-phenylethyleneglycol (MHPG). Saccadic, pursuit, and vestibulo-ocular eye movements were recorded using infrared oculography with subjects both on placebo and on metyrosine. The most consistent effect observed with metyrosine was an increase in the amplitude and frequency of saccadic intrusions during fixation and pursuit. Two of the 3 subjects also had shortened time constants for the vestibulo-ocular reflex, attributable in part to the sedative effect of catecholamine depletion. The increase in saccadic intrusions implies that catecholamines modulate the activity of a subpopulation of suppressor motor neurons in the human brainstem.

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.

Urinary free and conjugated catecholamines and metabolites in autistic children

Urinary catecholamines (DA, NE, E) and their main metabolites (HVA, DOPAC, MHPG) were analyzed both as free and conjugates in eight children diagnosed as autistic according to DSM-III criteria and eight normal children. Significant differences appeared for the urinary excretion of both DA and NE and their respective metabolites: Autistic children showed low DA, high HVA, high NE, low MHPG urinary levels. These results are consistent with previous findings on altered catecholamine metabolism in autistic children. They suggest that autistic behaviors might be related to an abnormal functional imbalance among monoamines either at a molecular level or at a system level. Furthermore, they emphasize the special interest of urinary assays in pediatric research.

Neuropsychological correlates of urinary amine metabolites in Tourette's syndrome

The relationships between neuropsychological performance and urinary amine metabolite levels (HVA, 5-HIAA, MHPG) were examined in a sample of 27 medication-free patients with Tourette's Syndrome. Correlations with specific metabolites indicated neuropsychological deficit associated with higher levels of HVA and lower levels of 5-HIAA. Variables computed to express the interaction of the various neurotransmitter systems provided strong and consistent support for such interactions in the underlying mechanism of the neurobehavioral deficits observed in these patients. The implications of these findings and directions for future research were discussed.

The 24-hour pattern of urinary MHPG excretion in depressives and normals

The 24-h pattern of urinary 3-methoxy-4-hydroxy-phenylglycol (MHPG) was studied in 15 depressives and 15 healthy controls. MHPG was measured at 3-h intervals over two consecutive 24-h periods. The shape of the MHPG excretion pattern of the depressed group was different from that of the control group. However, both the consistency and shape of the individual 24-h MHPG patterns exhibited a high interindividual variability. Therefore it is difficult to speculate on a circadian phase difference between depressives and healthy controls. Major factors that may have influenced our results are discussed.

Noradrenergic and serotonergic receptor system function in panic disorder and depression

Recent studies which have utilized the administration of neurotransmitter agonists and antagonists to study presynaptic and postsynaptic receptor system function in panic disorder and major depression are reviewed. In panic disorder, patients have been found to be overly sensitive to the alpha-2 adrenergic agonist clonidine, and the alpha-2-adrenergic antagonist yohimbine, but they have relatively normal responses to tryptophan, the precursor of serotonin, and MCPP, a directly acting serotonin agonist. In depression, patients appear to have relatively normal responses to clonidine and yohimbine except for some supersensitivity to yohimbine effects on blood pressure and subjective symptoms. In contrast to the panic disorder patients, depressed patients demonstrate a neuroendocrine subsensitivity to tryptophan. Taken together, these studies suggest a relative abnormality in the alpha-2-adrenergic regulation of the noradrenergic system in panic disorder and a subsensitivity of the serotonergic system in depression. The pharmacologic treatment response in panic disorder and depression is similar in that both conditions respond to tricyclic antidepressants and monoamine oxidase inhibitors, but different in that panic disorder does not respond to atypical antidepressants such as trazodone and bupropion, but does respond to benzodiazepines, in contrast to depression. The possible mechanisms involved in producing these findings and the methods to more fully study possible receptor system abnormalities in these illnesses are discussed.

The evaluation of 4-hydroxy-3-methoxyphenylglycol sulfate as a possible marker of central norepinephrine turnover. Studies in healthy volunteers and depressed patients

Much evidence indicates that urinary 4-hydroxy-3-methoxyphenylethyleneglycol (MHPG) is an insensitive measure of central norepinephrine metabolism. This conclusion, however, seems to apply mainly to total urinary MHPG, since previous findings point to the possibility that the major proportion of urinary MHPG sulfate originates in the CNS, while most urinary MHPG glucuronide originates in peripheral organs. To examine this hypothesis, experiments were performed by which we altered MHPG turnover in man at two different stages: firstly, strong physical exercise (ergometer) increased the urinary excretion rate of MHPG glucuronide and not that of MHPG-sulfate; secondly, ethanol (l g/kg), which is known to block the metabolism of MHPG to vanilmandelic acid in the liver, increases the urinary excretion rate of the glucuronide and not that of sulfate. Both experiments indicate that alteration of peripheral norepinephrine turnover changes the urinary excretion of MHPG glucuronide only and not that of sulfate, thus providing strong, albeit indirect, evidence for a primarily central origin of MHPG sulfate. Preliminary experiments in 32 depressed patients showed little difference in both MHPG fractions compared with healthy controls, apart from a slightly reduced excretion rate of glucuronide. These findings fail to provide any evidence of central, and only small changes in peripheral norepinephrine metabolism in depression.

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.

Noradrenergic function and hypothalamic-pituitary-adrenal axis activity in primary unipolar major depressive disorder

Plasma levels of cortisol, norepinephrine (NE), and 3-methoxy-4-hydroxyphenylglycol (MHPG) were found to be significantly higher in 16 drug-free patients with primary, unipolar major depressive disorder than in 20 controls. Plasma free MHPG and basal cortisol levels showed a significant positive correlation in the controls, but not in the patients. There were, however, significant positive correlations between cortisol and NE, as well as between NE and free MHPG levels in the patients. No correlations were observed between patient plasma NE levels and platelet alpha 2-adrenoceptor or lymphocyte beta-adrenoceptor Kd or Bmax values. These peripheral measures of noradrenergic function are proposed as useful markers for patients with primary, unipolar major depressive disorder with melancholia.

Norepinephrine and dopamine metabolites and educational variables in boys with attention deficit disorder and hyperactivity

The present study evaluated the biochemical measures of urinary homovanillic acid (HVA) and 3-methoxy-4-hydroxy-phenylglycol (MHPG) in relation to functioning on selected psychoeducational tests in a group of boys with attention deficit disorder and hyperactivity. The Wechsler Intelligence Scale for Children-Revised (WISC-R), the Wide Range Achievement Test (WRAT), and the Peabody Picture Vocabulary Test were administered to 28 hyperactive and 23 control subjects. The findings suggest subtle differences in psychoeducational test performance in relation to specific levels of homovanillic acid and MHPG.

Plasma 3-methoxy-4-hydroxyphenylethyleneglycol and homovanillic acid concentrations in patients with subarachnoid hemorrhage

To ask if the determination of central-nervous-system-derived catecholamine metabolites in peripheral circulation could be a useful index of brain dysfunction after subarachnoid hemorrhage, 3-methoxy-4-hydroxyphenylethyleneglycol and homovanillic acid concentrations in plasma, together with those of free catecholamines (noradrenaline, adrenaline, and dopamine), were serially measured for up to 3 weeks after the initiation of symptoms in 23 patients with aneurysmal subarachnoid hemorrhage as compared to 17 healthy and 9 patient controls. Catecholamines and their metabolites were determined by using high-performance liquid chromatography with electrochemical detection. Plasma 3-methoxy-4-hydroxyphenylethyleneglycol concentrations were markedly elevated in subarachnoid hemorrhage patients with coma compared to those without, and the maximal concentrations observed in comatose patients never occurred in normal subjects or in patients with other neurological disorders. The mean maximal plasma concentrations of free catecholamines did not differ significantly between the comatose and noncomatose groups. Combining 3-methoxy-4-hydroxyphenylethyleneglycol with homovanillic acid level data more clearly discriminated between the comatose and noncomatose subarachnoid hemorrhage groups. The results suggest that plasma concentration of 3-methoxy-4-hydroxyphenylethyleneglycol, a major metabolite of brain noradrenaline, can be a prognostic discriminator for patients with subarachnoid hemorrhage and its discriminating power can be strengthened by combining it with homovanillic acid data.