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PubMed1987

Direct concurrent measurement of urinary vanillylmandelic acid, 5-hydroxyindoleacetic acid and homovanillic acid by HPLC. Three methodologies compared.

Three different direct HPLC methods for the determination of 3-methoxy-4-hydroxymandelic acid (VMA, vanillylmandelic acid), 5-hydroxyindoleacetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylacetic acid (HVA, homovanillic acid) in urine were compared: two spectrofluorometric methods, applying discontinuous gradients, and one serial coulometric linear gradient method. The imprecision study (n = 6) revealed comparable coefficients of variation (CV), intra-assay ranging 1.4-11.1%, and inter-assay ranging 5.9-11.8% for physiological and moderately elevated levels of VMA, 5-HIAA and HVA. All methods showed good linearities up to 100 mumol/L for each of the three compounds studied. Analytical recoveries were 97-114% for VMA, 87-103% for 5-HIAA, and 80-95% for HVA. Recoveries were not dependent on urinary relative densities in the range 1.010-1.030 kg/L or on protein content (prior to acidification) in the range 0.1-3 g/L, or on the pH of conservation in the range 2-5 or on storage temperature in the range -20 - +22 degrees C for three weeks. The distributed-sample comparison revealed acceptable correlations and clinically unimportant accuracy differences between the methods. It is concluded that direct fluorometric and electrochemical HPLC methods can be used in the determination of major catecholamine and serotonin metabolites in human urine for clinical diagnosis and follow-up of neural crest and carcinoid tumours.

Chromatography, High Pressure Liquid↗
PubMed1987

Effect of L-DOPA, dopamine, dihydroxyphenyl acetic acid and homovanillic acid on Na,K-ATPase activity in rat proximal tubule segments.

We have recently demonstrated that dopamine (DA) inhibits Na,K-ATPase in single proximal tubule (PCT) segments dissected from previously collagenase perfused rat kidney. The aim of the present study was to ascertain whether this effect was directly mediated by DA or if DA was the precursor of an inhibitor. When PCT segments were incubated with L-DOPA, Na,K-ATPase was significantly lower than in vehicle incubated tubules. Inhibition of dopa decarboxylase abolished the effect of L-DOPA on Na,K-ATPase activity. The metabolites of DA, 3, 4-dihydroxphenyl acetic acid (DPAC) and homovanillic acid (HVA) both inhibited Na,K-ATPase activity in doses higher than 10(-6) M. Both HVA and DPAC 10(-4) M caused approximately 35% inhibition. Dopamine inhibited Na,K-ATPase activity even in a dose as low as 10(-7) M. Maximal inhibition (greater than 60%) was found with DA-5 M. Na,K-ATPase activity was significantly lower in tubules exposed to DA 10(-4) and 10(-5) M than in tubules exposed to DPAC or HVA 10(-4) and 10(-5) M. Dopamine produced in proximal tubule cells from L-DOPA, is an active inhibitor of the Na,K-pump in these cells. The DA metabolites DPAC and HVA are less potent Na,K-pump-inhibitors.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

[Excretion of vanillic acid and homovanillic acid and tissue distribution of catecholamines and their metabolites in mice with various levels of pigmentation].

Studies concerning metabolism of catecholamines in mice differing with respect to the degree of pigmentation were based on determination of daily excretion of vanillylmandelic and homovanillic acid and tissue content of epinephrine, norepinephrine, dopamine and their methoxy derivatives. It was found that pigmented mice excrete more homovanillic acid, the metabolite of dopamine, than do albinotic mice. Tissue studies have shown that the brain of albinotic mice contains more dopamine and kidneys more epinephrine, norepinephrine and their methoxy derivatives than the respective organs of the pigmented mice. The probable reasons of differences in the rate of inactivation of catecholamines in albinotic and pigmented mice have been discussed.

Animals↗
PubMed1985

Relationship between dominance hierarchy, cerebrospinal fluid levels of amine transmitter metabolites (5-hydroxyindole acetic acid and homovanillic acid) and plasma cortisol in monkeys.

The dominance hierarchy has repercussions for a monkey's sexual behaviour and endocrine state. Here we report on neural mechanisms that are sensitive to a monkey's status in the social hierarchy, and which may regulate not only its endocrine function but its sexual responsiveness to its own hormones. During the initial phase of group formation, 5-hydroxyindole acetic acid, the metabolite of serotonin, increases in the cerebrospinal fluid of monkeys which become subordinate (all groups), but decreases in monkeys which become dominant (two out of three groups) and shows no changes in intermediate-ranking animals (five out of seven). Homovanillic acid, a metabolite of dopamine, may also increase in the cerebrospinal fluid of monkeys that become subordinate (two out three groups). In the initial period of group formation these changes in transmitter metabolites do not parallel changes in cortisol. However, in the established social groups, both 5-hydroxyindole acetic acid and plasma cortisol are related to the social hierarchy, being greater in those monkeys that are subordinate, but homovanillic acid shows no consistent change. Although subordinate monkeys receive more aggression than others in their group, fluctuations in 5-hydroxyindole acetic acid do not correlate with aggressive behaviour, and are equally high on days when no aggression occurs. Dominant males, however, had higher 5-hydroxyindole acetic acid levels on days when they were involved in agonistic encounters. In the established social hierarchy therefore, elevated levels of the serotonin metabolite in cerebrospinal fluid seem reflect a "state"-dependent consequence of occupying a position of low social status.

Animals↗
PubMed1981

Enhancement of haloperidol-induced increase in rat striatal or mesolimbic 3,4-dihydroxyphenylacetic acid and homovanillic acid by pretreatment with chronic methamphetamine.

After a drug-free period of 1 week following 2 weeks of haloperidol treatment, the increased response of striatal 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) to a challenge dose of haloperidol was significantly reduced. Tolerance to this effect was not, however, seen in the mesolimbic system. Pretreatment of the rats with methamphetamine (MAP) for 8 days prior to chronic haloperidol significantly enhanced the DOPAC and HVA increase produced by the challenge with haloperidol in both brain areas. The reduced response of striatal DOPAC or HVA after chronic haloperidol was prevented by pretreatment with MAP. The data suggest that the long-term dopamine receptor stimulation induced by MAP may antagonize the tolerance produced by chronic haloperidol treatment.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2002

Simultaneous determination of 3,4-dihydroxyphenylacetic acid and homovanillic acid using high performance liquid chromatography-fluorescence detection and application to rat kidney microdialysate.

We established a sensitive and simultaneous determination method of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) using HPLC-fluorescence detection. This method adopted the column-switching system, which included an on-line extraction of carboxylic acids by a strong anion-exchange column followed by separation on an ODS column, coulometric oxidation, fluorogenic reaction with ethylenediamine, and fluorescence detection. The detection limits were 50 and 100 fmol/injection for DOPAC and HVA, respectively (a signal-to-noise ratio of 3). The method was applicable to 50 microl of rat kidney microdialysate with a sufficient accuracy and precision. The concentrations of DOPAC and HVA in rat kidney microdialysate were 131+/-29 and 404+/-44 nM, respectively (n=5). This is the first report of DOPAC and HVA quantified in rat kidney microdialysate.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1976

Regional rat brain levels of 3,4-dihydroxyphenylacetic acid and homovanillic acid: concurrent fluorometric measurement and influence of drugs.

A concurrent semi-automatic fluorometric assay technique for 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), is described. The method is based on a rapid manually performed isolation of DOPAC and HVA on small columns of Sephadex G-10 followed by an automated fluorometric detection with a continuous flow system. DOPAC and HVA were measured in the corpus striatum, nucleus accumbens and olfactory tubercle of the rat, under normal conditions and after treatment with amphetamine, apomorphine, clozapine, haloperidol, morphine, oxotremorine, pargyline, probenecid, sulpiride and thioridazine. Clozapine, morphine, sulpiride and oxotremorine induced the most pronounced rise of DA metabolites in the nucleus accumbens. Probenecid produced a DOPAC accumulation in the nucleus accumbens. Striking differences were observed between the DOPAC/HVA ratios in the different structures of control animals. The concurrent assay enables a rapid screening of the action of drugs in regional DA metabolism.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1982

Long-term decreases in striatal dopamine, 3,4-dihydroxyphenylacetic acid, and homovanillic acid after a single injection of amphetamine in iprindole-treated rats: time course and time-dependent interactions with amfonelic acid.

The administration of a single dose of (+)-amphetamine sulfate (9.2 mg/kg) to rats treated with iprindole hydrochloride (10 mg/kg) produced marked decreases in the striatal concentrations of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) one week after drug administration. Significant changes were not observed in striatal 5-hydroxyindoleacetic acid (5-HIAA) nor in norepinephrine, DA, DOPAC, HVA, and 5-HIAA concentrations in frontal cortex and a limbic forebrain sample containing primarily nucleus accumbens and olfactory tubercles. In time-course experiments, decreases in striatal DA were apparent by 12 h after amphetamine plus iprindole administration and persisted for at least 4 weeks. Decreases in striatal DOPAC and HVA followed a similar time course, except decreases in these parameters were observed at 6 h as well. The administration of amfonelic acid, a potent DA uptake inhibitor, up to 8 h but not at 12 h after amphetamine administration prevented the decreases in striatal DA, DOPAC and HVA at on week after the administration of the drug to iprindole-treated rats. These data indicate that the actions of amphetamine which are necessary and sufficient for the production of long-term decreases in striatal DA, DOPAC and HVA are dependent upon the integrity of the neuronal uptake mechanism for DA and occur within 12 h after the administration of amphetamine to iprindole-treated rats. Although amfonelic acid prevented the long-term effects of amphetamine on striatal DA neurons, it did not alter the decrease in DOPAC produced by amphetamine at 6 h after the administration of amphetamine plus iprindole. This finding suggests that the ability of amfonelic acid to prevent the long-term effects of amphetamine on striatal DA neurons in iprindole-treated rats is not due to a blockade of the entry of amphetamine into the neuron and, thus, suggests that the access of amphetamine to the inside of the neuron is not sufficient for the production of its long-term, possibly neurotoxic, effects n striatal DA neurons.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1986

Free and conjugated 3,4-dihydroxyphenylacetic acid and homovanillic acid in brain dopaminergic areas at basal state and after pipotiazine activation.

We have determined free and conjugated 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in discrete brain areas of rats. Conjugated HVA or DOPAC accounted for 22-38% of total acids in striatum, mesolimbic tissue or prefrontal cortex. Activation of dopamine (DA) metabolism by a single injection of pipotiazine palmitic ester (PPZ), a long-lasting neuroleptic, increased free acid levels (DOPAC and HVA) at either dose and conjugate levels after 32 or 50 mg/kg. 48 hours after PPZ-32 mg/kg, the observed increases of conjugates could exceed in some cases those of corresponding free acids. About half of total DOPAC and HVA were conjugated in hypothalamus, PPZ moderately increased free DOPAC (at 32 mg/kg) but did not elevate significantly the conjugated form. It is concluded that sulfation is an important pathway for DOPAC and HVA metabolism in brain and that the determination of both free and conjugated DOPAC or/and HVA may shed additional lights on regional DA metabolism and the effect of drugs thereon.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1976

Effect of probenecid on endogenous and exogenous 3,4-dihydroxyphenylacetic acid and homovanillic acid in the rat brain.

The two dopamine metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were measured in corpus striatum and hippocampus in rats after an intracerebroventricular injection of DOPAC or HVA. Probenecid 200 mg/kg i.p. increased the concentration of HVA by the same factor in both control animals and animals treated with HVA. Probenecid had no effect on the DOPAC concentration in control animals or in animals treated with DOPAC. After DOPAC intraventricularly some increase in the HVA concentration could be seen. Pargyline 75 mg/kg was given i.m. and the decline of HVA and DOPAC in corpus striatum was compared in animals with or without probenecid treatment (200 mg/kg i.p.). In the control animals DOPAC declined more rapidly than did HVA. In the probenecid-treated animals there was no change in the DOPAC curve while the HVA showed a slower elimination but still with an exponential curve. The conclusion is drawn that there is an active mechanism for the excretion of DOPAC which is not identical with the excretion mechanism for HVA. A considerable part of the dopamine is directly deaminated to DOPAC in vivo and some of this DOPAC is probably O-methylated to HVA.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1979

3,4-Dihydroxyphenylacetic acid and homovanillic acid in rat plasma: possible indicators of central dopaminergic activity.

The concentrations of dopamine (DA) metabolites (free and conjugated) was measured in plasma and brain regions of rats by the mass spectrometric method of selected ion monitoring. Experimental treatments which altered the function of central dopamine neurons also induced concomitant changes in plasma 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). Stimulation of the nigrostriatal pathway increased plasma DOPAC and HVA whereas lesion of the pathway decreased plasma metabolites. Several drug treatments induced parallel changes in brain and plasma concentrations of DA metabolites. It is suggested that changes in the concentration of DOPAC and HVA in rat brain are reflected by parallel changes in plasma. No conjugated forms of DOPAC and HVA were found in plasma and brain tissue of vervet monkeys (Cercopithecus aethiops).

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Pharmacological evidence, using in vivo dialysis, that substances additional to ascorbic acid, uric acid and homovanillic acid contribute to the voltammetric signals obtained in unrestrained rats from chronically implanted carbon paste electrodes.

In vivo voltammetry at chronically implanted carbon paste electrodes in unrestrained rats is a particularly useful technique for evaluating neurochemical changes during spontaneous behaviour, or behaviour under experimental control. A 3 peak signal is observed in the striatum; most recently the consensus view has attributed these peaks to ascorbic acid (AA), uric acid (UA) and homovanillic acid (HVA) in ascending order of oxidation potential. We have used a pharmacological approach, combined with in vivo dialysis, to further elucidate the nature of the contributing species. Allopurinol, an inhibitor of xanthine oxidase, and thus of uric acid production, has previously been reported to abolish peak 2. We now report, using dialysis, that it selectively depletes UA in the extracellular fluid (ECF). Pargyline, a monoamine oxidase inhibitor, reduces peak 3 transiently (max. 60%) as expected, however it results in a more sustained reduction in ECF HVA (max. 100%). It also increases peak 1 (max. 75%) and decreases peak 2 (max. 40%), although changes in ECF AA and UA measured by dialysis and HPLC are minimal. Pargyline does however reduce ECF 5-hydroxyindoleacetic acid by 65%. We conclude that, using linear sweep voltammetry at chronically implanted paste electrodes: (a) one or more substances in addition to AA can contribute to peak 1; dopamine can do so in some situations; (b) 5-hydroxyindoleacetic acid, as well as UA, contributes to peak 2; its contribution is about one third that of the latter; and (c) one or more substances in addition to HVA can contribute to peak 3. 3-Methoxytyramine can do so. Since this is another methylated metabolite of dopamine, this does not prevent the use of peak 3 as an index of dopamine metabolism, and may extend its usefulness to situations where monoamine oxidase is inhibited.

Allopurinol↗
PubMed1990

Effects of phencyclidine on extracellular levels of dopamine, dihydroxyphenylacetic acid and homovanillic acid in conscious and anesthetized rats.

Dose-dependent effects of phencyclidine on extracellular levels of dopamine (DA), dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the neostriatum were studied in both urethane-anesthetized and conscious rats. In vivo microdialysis was used to collect 10 min samples that were analyzed for levels of DA, DOPAC and HVA, using high-performance liquid chromatography with electrochemical detection (HPLC-EC). In both the anesthetized and conscious preparations, 20 mg/kg of phencyclidine produced an increase in extracellular levels of DA, 10 mg/kg resulted in no change, while 1 mg/kg produced a slow decrease. In the anesthetized animals phencyclidine did not have a significant effect on levels of DOPAC or HVA, but in the conscious animals phencyclidine produced a dose-dependent decrease in levels of DOPAC and HVA. The increase in levels of DA could be the result of increased release of DA or inhibition of the uptake of DA. The decrease in levels of DOPAC and HVA, at the 1 mg/kg dose, could result from a decrease in the synthesis of DA that is offset at the 10 and 20 mg/kg doses by opposing mechanisms.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1982

Influence of UV- and capsaicin-induced erythema as well as of acetylsalicylic acid on the urinary excretion of vanilmandelic acid and homovanillic acid in man.

In the present study we investigated whether by means of urinary excretion of vanilmandelic acid (VNA) and homovanillic acid (HVA), resp., the two main metabolites of adrenaline, noradrenaline and dopamine, informations could be obtained on synthesis and release of catecholamines in inflammation. UV- and capsaicin-induced erythema, resp., were used as the inflammatory models. The urinary excretion or both VMA and HVA were found to be decreased after UV irradiation. Administration of acetylsalicylic acid during UV irradiation inhibited the decrease of VMA excretion whereas HVA excretion remained low. The application of capsaicin as a plaster failed to influence the urinary VMA and HVA excretion. Our results could be explained on the basis of the interrelationship between catecholamines and prostaglandins. Other possible mechanisms are discussed.

Adult↗
PubMed1984

Gamma-aminobutyric acid and homovanillic acid concentration in the CSF of patients with senile dementia of Alzheimer's type.

The investigation of enzyme and neurotransmitter levels and/or their metabolites in the CSF of patients with senile dementia of Alzheimer's type (SDAT) could become a promising approach for a clinical research and diagnostic procedure. To learn more about the metabolic reflections of central metabolism in the CSF of patients with SDAT, we measured CSF levels of gamma-aminobutyric acid (GABA) and homovanillic acid (HVA), the dopamine metabolite. In 16 female patients with SDAT and in eight matched control patients, CSF GABA levels were measured by ion exchange with fluorimetric detection, and HVA levels were measured fluorimetrically. The GABA content of the CSF was significantly reduced in patients with SDAT, whereas the HVA level was unchanged.

Aged↗
PubMed1986

Determination of urinary vanillylmandelic acid and homovanillic acid by high performance liquid chromatography for mass screening of neuroblastoma.

In order to develop a mass screening method for the early detection of neuroblastoma, we measured urinary vanillylmandelic acid (VMA) and homovanillic acid (HVA) by a high performance liquid chromatography (HPLC) equipped with an electrochemical detector. Urinary samples were collected on a piece of filter paper and then pre-treated by a simple method. Measurement of VMA and HVA was performed within a short period of time, and by about 80 samples per a day could be analyzed by automatic system. The method described herein proved to be reliable, and we thus recommend it as a useful method for measurement of both VMA and HVA, leading to more accurate detection of neuroblastoma in mass screening test.

Chromatography, High Pressure Liquid↗
PubMed1982

Cerebrospinal fluid gamma-aminobutyric acid and homovanillic acid in depressive disorders.

gamma-Aminobutyric acid (GABA) and homovanillic acid (HVA) levels were determined in the lumbar cerebrospinal fluid (CSF) of hospitalized patients suffering from depression and in a control group. Both mean CSF GABA and HVA levels in the patients with depression were significantly lower than those of the control group (p less than 0.05, p less than 0.01, respectively). No positive correlation was found between the changes in CSF GABA and HVA levels in the patients with depression. The Hamilton Rating score in these depressed patients, age, and sex showed no correlation to CSF GABA levels. It is suggested that decreased activity in the central GABAergic and dopaminergic system may be involved in the pathogenesis of depression.

Adult↗
PubMed1987

Establishment of cut off values for vanillylmandelic acid and homovanillic acid in 24-hr urine accumulation during mass screening for neuroblastoma.

The establishment of cut off values in vanillylmandelic acid (VMA) and homovanillic acid (HVA) in 24-hr urine specimens for the purpose of separating true positive cases from normal infants has been discussed. The specimens were collected at the time when thorough examinations under a mass screening programme for neuroblastoma were taking place, and data from 17 infants with neuroblastoma (patients) and 50 healthy infants (controls) have been employed. The function square root VMA2 + HVA2 = 34 (micrograms/mg of creatinine) separated the two groups with no overlapping cases. This function represents the distance from the origin of the VMA-HVA co-ordinates, and is thought to be one of the most reasonable discriminant methods when considering the distribution pattern of the data for normal cases and patients.

Chromatography, High Pressure Liquid↗