Selected ion monitoring assay for biogenic amine metabolites and probenecid in human lumbar cerebrospinal fluid

Lipidomic profiling of mastoid bone and tissue from patients with chronic otomastoiditis

Introduction Chronic otomastoiditis causes pain, otorrhea, and hearing loss resulting from the growth of tissue within the normally hollow mastoid cavity.

Objectives In this report, we used a lipidomics approach to profile major mastoid bone and tissue lipids from patients with and without otomastoiditis.

Methods The bone dust created during mastoidectomy, as well as the mastoid tissue, was analyzed from seven patients. Bone dust was also collected and analyzed in an additional four otologic cases (parotidectomy requiring mastoidectomy). Samples were subjected to a modified Bligh/Dyer lipid extraction, then high-performance thin-layer chromatography (HPTLC), combined gas chromatography/electron impact-mass spectrometry (GC/EI-MS), and flow-injection/electrospray ionization-tandem mass spectrometry (FI/ESI-MSMS). Data were analyzed for identification and profiling of major lipid components.

Results HPTLC revealed the presence of various lipid classes, including phosphatidylcholines, cholesterol, and triacylglycerols. GC/EI-MS analysis revealed the presence of cholesterol and several fatty acids. FI/ESI-MSMS analysis revealed a host of phosphatidylcholines, phosphatidylethanolamines, and cholesteryl esters.

Conclusion We used a lipidomics approach to develop an efficient (both in time and tissue amount) methodology for analysis of these tissues, identify the most abundant and common lipid species, and create a base of knowledge from which more focused endeavors in biomarker discovery can emerge. In an effort toward improved patient categorization and individualized intervention, the ultimate goal of this work is to correlate these lipid molecules to disease state and progression. This is the first reported study of its kind on these tissues.

Lipidomic profiling of sinus mucosa from patients with chronic rhinosinusitis

Sinusitis is a cause of significant morbidity, substantial healthcare costs, and negative effects on quality of life. The primary objective of this study is to characterize the previously unknown lipid profile of sinonasal mucosa from patients with chronic rhinosinusitis (CRS) and from controls. Sinus mucosa samples were analyzed from 9 CRS patients with concomitant nasal polyps, 11 CRS patients without polyps, and 12 controls. Ten lone polyp samples were also analyzed. Samples were subjected to a modified Bligh/Dyer lipid extraction, then high performance thin layer chromatography (HPTLC), combined gas chromatography/electron impact-mass spectrometry (GC/EI-MS), and flow-injection/electrospray ionization-tandem mass spectrometry (FI/ESI-MS/MS). Data was analyzed for identification and profiling of major components. HPTLC revealed an array of species reflecting the lipid complexity of the samples. GC/EI-MS revealed cholesterol and several fatty acids. FI/ESI-MSMS revealed numerous lipid species, namely a host of phosphatidylcholines, phosphatidylethanolamines, ceramides and cholesteryl esters, but no detectable amounts of phosphatidyinositols or sulfated lipids. These results are a first step to uncover unique molecular biomarkers in CRS.

The long-term psychobiological consequences of intermittent postnatal separation in the squirrel monkey

Long-term effects of early experiences have been well documented in rodents, non-human primates and humans. The influence of early experiences on the regulation of the hypothalamic-pituitary-adrenal has demonstrated that this biological system is highly plastic and is permanently modified by early experiences. The effects of brief periods of maternal separation in rodents tend to result in a reduction of the stress response, whereas longer periods of maternal separation produce an animal that is hyperresponsive. The effect of disruptions of mother-infant interactions on the HPA axis in non-human primates has not been clearly established. However, the primate research has primarily focused on more permanent separation paradigms and thus it is difficult to compare the rodent studies with those conducted in primates. The present study attempted to use a separation procedure in monkeys that more closely resembled the rodent model. Intermittent separation during infancy followed by reunion with the mother were shown to lead to a significant reduction in both the cortisol response and the response of the noradrenergic system following social isolation in juvenile squirrel monkeys at 2 and 3 years of age. The behavioral response (vocalizations) was also reduced.

N-acetylaspartic acid (NAA) and N-acetylaspartylglutamic acid (NAAG) in human ventricular, subarachnoid, and lumbar cerebrospinal fluid

N-Acetylaspartic and N-acetylaspartylglutamic acid concentrations in human ventricular, subarachnoid and lumbar cerebrospinal fluid were measured by combined gas chromatography-mass spectrometry using selected ion monitoring with deuterated internal standards. N-Acetylaspartate concentrations were in the range 55, 9, and 1 microM, respectively; N-acetylaspartylglutamate concentrations in the same fluids were in the range 8, 3 and 4 microM, respectively. There did not appear to be any difference in lumbar fluid concentrations of either compound between control subjects, schizophrenic patients, Alzheimer's disease patients and a pooled group of patients with neurological degeneration. Ventricular concentrations of both compounds were greatly increased in deceased patients suggesting that maintenance of their intracellular concentrations is probably energy dependent. The concentrations of these compounds in lumbar cerebrospinal fluid from living, and ventricular cerebrospinal fluid from deceased subjects were weakly correlated with one another. In lumbar fluid neither compound appeared to be correlated with age. Analysis of serially collected lumbar samples from two subjects showed a weak concentration gradient for both compounds. Neither antipsychotic medication nor the acid transport inhibitor probenecid had any effect on lumbar concentrations of either compound. Attempts to use anion exchange high pressure liquid chromatography with UV detection for measurement of the low concentrations of N-acetylaspartate found in cerebrospinal fluid from living subjects were unsuccessful.

Cerebrospinal fluid glutamate inversely correlates with positive symptom severity in unmedicated male schizophrenic/schizoaffective patients

BACKGROUND

Recent hypotheses have suggested that diminished brain glutamate may be of importance in the neurochemical basis of schizophrenia.

METHODS

We assayed cerebrospinal fluid for glutamate and obtained clinical symptom ratings in 19 medication-free (except p.r.n. chloral hydrate) schizophrenic or schizoaffective (typically with significant schizophrenic qualities) male inpatients.

RESULTS

Ratings of positive symptoms were significantly inversely correlated (rs = -.457, p < .05, one-tailed test) with glutamate concentrations. Hallucinatory behavior was strongly correlated (rs = -.621, p < .01, one-tailed test) with glutamate. A subset of 11 patients consented to a second lumbar puncture (LP) after treatment with haloperidol (typically 15 or 20 mg/day) for 2-4 weeks. Haloperidol treatment did not alter glutamate concentrations. No correlations were noted between glutamate and symptoms in the medicated subsample. Though approximately half the patients received chloral hydrate during the 72 hours prior to the unmedicated LP, the correlations between positive symptoms and glutamate in the patients who received no chloral hydrate prior to the LP were quite similar to those found in the overall sample.

CONCLUSIONS

The results provide further support for the potential importance of glutamate in the neurochemical basis of schizophrenia.

CSF and plasma MHPG, and CSF MHPG index: pretreatment levels in diagnostic groups and response to somatic treatments

The authors report a significant positive correlation between levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) in cerebrospinal fluid (CSF) and plasma in drug-free affective disorder patients (major depression, mania, and schizoaffective disorder), but not in schizophrenia. Recent kinetic studies on the relationship between plasma and CSF MHPG discourage the interpretation of independent CSF MHPG levels without correction for the diffusion of MHPG across the blood-brain barrier. The authors therefore examine pretreatment CSF and plasma MHPG levels, and the CSF MHPG index (CSF MHPG corrected for by using simultaneously obtained plasma MHPG according to the method of Kopin et al. [1983]). No significant differences were found in these pretreatment MHPG measures among the four diagnostic groups. Changes in these MHPG indices, and their correlations with behavioral rating scores, are also examined with respect to response to the four major somatic therapies (neuroleptics, lithium, antidepressants, and electroconvulsive therapy).

An association between low levels of 5-HIAA and HVA in cerebrospinal fluid and early mortality in a diagnostically mixed psychiatric sample

We followed up a sample of psychiatric patients (diagnoses predominantly schizophrenia and depression) who had participated in in-patient studies of their CSF over the past 15 years. The status of 73 former patients was confirmed, of whom 12 had died. Seven of these patients died at age < or = 40, largely of suicide, homicide, or accidental causes. These seven patients had significantly lower CSF 5-HIAA and HVA than living control patients. There were significant direct correlations between age at death and both CSF 5-HIAA and HVA in the deceased patients. The results offer support for CSF monoamine metabolites relating to early death in a diagnostically diverse sample of psychiatric patients.

Homovanillic acid in the cerebrospinal fluid: patterns of response after four weeks of neuroleptic treatment

Lumbar cerebrospinal fluid (CSF) homovanillic acid (HVA) concentrations were measured before and after 4 weeks of neuroleptic treatment in schizophrenic (n = 15) and schizoaffective (n = 4) patients. Neuroleptic treatment induced a nonsignificant (17%) increase in CSF HVA group mean levels. For the total group, no correlations were found between pretreatment CSF HVA and clinical measures, or between changes in HVA and clinical response. An alternative interpretation was attempted by defining "tolerant" and "nontolerant" subgroups. A "tolerant" response was defined as a reduction in posttreatment HVA values below pretreatment levels, whereas a "nontolerant" response was characterized by posttreatment values above pretreatment levels. When thus defined, nontolerant patients had a significantly inferior clinical response to neuroleptics, in contrast to their tolerant counterparts. Further, although there was no difference in pretreatment CSF HVA values between these two groups, pretreatment clinical profiles did differ significantly. Also, in a retrospective analysis, nontolerant patients were found to have a significantly earlier age of illness onset, a greater number of prior psychiatric hospitalizations, and more time spent in psychiatric hospitals.

MMPI measures of impulsivity and depression correlate with CSF 5-HIAA and HVA in depression but not schizophrenia

Recent studies have linked impulsivity with CSF concentrations of both 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA). One work found a negative correlation between the MMPI psychopathic deviate (Pd) scale and 5-HIAA in personality disordered men (Brown et al., 1982). We found that the 5-HIAA/Pd correlation extends (P less than 0.05) to unmedicated depressed patients (n = 21). A trend was found between HVA and Pd in depression. There was no relationship between either metabolite and the Pd scale in unmedicated schizophrenics (n = 24). A significant inverse correlation was found between the MMPI depression scale and CSF HVA but not 5-HIAA in the depressed patients.

Passage of MHPG from plasma to CSF in a non-human primate

In experimental protocols with humans and non-human primates, cerebrospinal fluid (CSF) concentrations of 3-methoxy-4-hydroxyphenylethylene glycol (MHPG), the predominant end-product of norepinephrine metabolism in the mammalian central nervous system (CNS), have been widely used as an index of the rate of CNS norepinephrine metabolism. However, an earlier investigation showed that there was slow but free exchange between plasma and CSF MHPG. To define more precisely the time-course of equilibration of plasma and CSF MHPG, we intravenously administered 100 micrograms/kg of [2H3]-MHPG to drug-naive squirrel monkeys. Measurements were made of the concentrations of [2H3]- and [1H]-MHPG in plasma and cervical CSF samples collected at time points from 10 min to 4 hr thereafter. The results indicated that neither plasma nor CSF concentrations of [1H]-MHPG changed during the course of the experiment, and that [2H3]-MHPG appeared in the CSF within 10 min of intravenous administration. The maximal plasma and CSF concentrations of [2H3]-MHPG were 7.6- and 2.3-fold higher than the respective concentrations of [1H]-MHPG. The plasma and CSF pools of [2H3]-MHPG reached concentration equilibrium within 30 min, and thereafter the temporal decline in concentration of [2H3]-MHPG was the same in plasma and CSF. These results demonstrate that MHPG rapidly crosses from plasma to CSF, and support the suggestion that this factor be included in any attempts to estimate norepinephrine turnover in the CNS from measurements of steady-state MHPG concentrations in CSF or plasma.

Intercorrelations among monoamine metabolite concentrations in human lumbar CSF are not due to a shared acid transport system

Intercorrelations among homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and 3-methoxy-hydroxy-phenylglycol (MHPG) concentrations in lumbar cerebrospinal fluid (CSF) were examined before and after blockade of the acid transport system by probenecid in 59 psychiatric inpatients. The three compounds remained intercorrelated despite acid transport blockade, suggesting that the common transport system does not account for their covariance. Other possibilities to explain the interrelationship among these compounds are discussed.

CSF 5-HIAA, serum cortisol, and age differentially predict vegetative and cognitive symptoms in depression

Prior studies have shown that both cerebrospinal fluid (CSF) concentrations of 5-hydroxyindolacetic acid (5-HIAA) and serum cortisol levels are related to overall symptom severity in depression. In the present study, 30 unmedicated inpatients meeting Research Diagnostic Criteria (RDC) criteria for depression participated in serum cortisol collection and a lumbar puncture for CSF. A multiple regression evaluated the ability of CSF 5-HIAA, serum cortisol, and age to predict cognitive and vegetative symptom clusters of the Hamilton Rating Scale for Depression. The multiple regression to predict the vegetative symptom cluster was highly significant overall (p = 0.002) and found that age and cortisol but not 5-HIAA predicted vegetative symptoms. The regression to predict the cognitive cluster narrowly missed overall significance (p = 0.06). Both CSF 5-HIAA and serum cortisol predicted cognitive symptoms and 5-HIAA predicted the cognitive cluster more strongly than cortisol. Age did not predict cognitive symptoms. The results suggest a dissociation between serum cortisol levels and CSF 5-HIAA in predicting vegetative and cognitive symptom clusters in depression.

Postmortem changes in the levels of monoamine metabolites in human cerebrospinal fluid

Four monoamine metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylglycol (MHPG) and 5-hydroxyindoleacetic acid (5-HIAA), were determined in the cerebrospinal fluid (CSF) of cadavers, whose causes of death had been suicidal hanging (SH) or ischemic heart failure (IHF). The concentration of DOPAC increased in parallel with the increment of the postmortem interval (PMI) (r = 0.626), whereas the concentrations of HVA, MHPG and 5-HIAA did not. The correlation coefficient was further increased by considering each cause of death separately: i.e., SH, r = 0.761; IHF, r = 0.705. These findings suggest the possible usefulness of the DOPAC level in CSF for estimating PMI.

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.

Measurement of catecholamines, their precursor and metabolites in human urine and plasma by solid-phase extraction followed by high-performance liquid chromatography with fluorescence derivatization

A high-performance liquid chromatographic method is described for the determination in human urine and plasma of catecholamines, their precursor and metabolites [amino compounds (norepinephrine, epinephrine, dopamine, normetanephrine, metanephrine, 3-methoxytyramine and L-DOPA), acidic compounds (3,4-dihydroxymandelic acid, 3,4-dihydroxyphenylacetic acid, vanillylmandelic acid and homovanillic acid) and alcoholic compounds (3,4-dihydroxyphenylethyleneglycol and 4-hydroxy-3-methoxyphenylethyleneglycol)]. Urine (0.5 ml) containing 3,4-dihydroxybenzylamine and 4-hydroxy-3-methoxycinnamic acid (internal standards) is deproteinized with perchloric acid, and the resulting solution is fractionated by solid-phase extraction on a strong cation-exchange resin cartridge (Toyopak IC-SP S) into two fractions (amine fraction and acid-alcohol fraction), which include 3,4-dihydroxybenzylamine and 4-hydroxy-3-methoxycinnamic acid, respectively. Plasma (0.7 ml) is deproteinized in the presence of 3,4-dihydroxybenzylamine (internal standard) in the same manner, and the resulting solution is directly used as an acid-alcohol fraction, while an amine fraction is obtained as for urine. Each fraction is subjected to the previously established ion-pair reversed-phase chromatography with post-column derivatization involving coulometric oxidation followed by fluorescence reaction with 1,2-diphenylethylenediamine. The detection limits, at a signal-to-noise ratio of 5, of the compounds measured in urine are 300 pmol/ml for the two mandelic acids, 2-7 pmol/ml for the other acidic and alcoholic compounds, 12 pmol/ml for L-DOPA and 0.6-2 pmol/ml for the other amino compounds; the corresponding values for plasma samples are 80, 0.5-3, 10 and 0.6-3 pmol/ml, respectively.

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.

Plasma and CSF HVA before and after pharmacological treatment

Plasma and cerebrospinal fluid (CSF) levels of the major dopamine metabolite homovanillic acid (HVA) were measured in psychiatric patients after an average washout period of 19 days, and again after 4 weeks of pharmacological treatment. Absolute values of plasma HVA did not correlate with absolute values of CSF HVA either at baseline or after treatment. However, changes in plasma HVA were highly correlated with changes in CSF HVA. Further, while baseline levels of plasma and CSF HVA were not significantly correlated with baseline clinical measures, clinical improvement was associated with decreases in both plasma and CSF HVA. This reached statistical significance for the plasma HVA level/clinical response relationship.

Catecholamines and their metabolites

The research on biosynthesis, physiology, pharmacology, regulation and degradation of catecholamines has continuously increased for more than 50 years. This is not unexpected because of the fact that catecholamines are involved in so many life processes such as nerve conduction, blood circulation and hormone regulations in health and disease. This demands that methods for their determination should be improved, and in fact during the years a number of analytical methods have been published. About 20 years ago radioenzyme techniques with thin-layer chromatographic (TLC) separation of radiolabelled catecholamine derivatives were developed which greatly contributed to our knowledge of physiological concentrations of catecholamines in biological media, particularly in plasma and brain. Radioimmune methods were successful for analysis of a number of analytes, but for catecholamines radioimmunoassays developed slowly. We believe that the greatest potential for radioimmunochemical methods lies in their ability to localize catecholamines and metabolites at the cellular and subcellular levels. With the advent of gas chromatographic-mass spectrometric (GC-MS) and high-performance liquid chromatographic (HPLC) procedures analysis of catecholamines improved greatly., The equipment for GC-MS is expensive and requires technical skillfulness, but in experienced hands a lot of new biological data have emerged. An outstanding quality with GC-MS is that the method offers the ability to identify unknown compounds and is relatively free from interferences from extraneous compounds. In comparison with GC-MS, HPLC is versatile and has gained a widespread use. Applications for research in the catecholamine field are numerous. In general, the sensitivity and specificity are satisfactory with HPLC, but it should be borne in mind that a number of pitfalls can obscure the results. This involves both sample handling, clean-up and chromatographic procedures. At present, HPLC is the most expanding field in chromatographic determination of catecholamines and their metabolites. This is particularly the case for HPLC with electrochemical detection which has revolutionized our analytical potential in this field. These chromatographic procedures continue to develop. The prerequisites for further improved methods such as capillary zone electrophoresis and combined HPLC-MS are at hand and hopefully will soon come into more general use for analysis of catecholamines in biological samples.

TRH stimulation test and depression

A thyrotropin-releasing hormone (TRH) stimulation test was performed in 52 male inpatients with major depressive disorder. Twenty-nine percent of the 52 subjects had a delta thyroid-stimulating hormone (delta TSH) less than 5 microU/ml. The cerebrospinal fluid (CSF) amine metabolites, 3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5HIAA), were measured in 29 subjects, and a dexamethasone suppression test (DST) was performed in 48 subjects. Of the three CSF amine metabolites, only MHPG correlated significantly with baseline TSH and none correlated with delta TSH. The baseline TSH correlated positively with the TSH response at 30 minutes. Neither baseline TSH nor delta TSH correlated with cortisol levels before or after dexamethasone. The correlation between CSF MHPG and serum TSH suggests a relationship between central norepinephrine and baseline TSH.

CSF amine metabolites and depression

Cerebrospinal fluid (CSF) amine metabolites were measured in 37 male subjects with major depressive disorder. Scores on the Hamilton Rating Scale for Depression (HRSD) correlated significantly with 5-hydroxyindoleacetic acid (5HIAA) and with homovanillic acid (HVA). In addition, the single suicide item of the HRSD correlated significantly with 5HIAA. Further, 5HIAA and HVA correlated significantly with each other. There was a significant positive correlation between HVA and two HRSD items, the depersonalization/derealization item and the paranoid item. Since lumbar CSF metabolite concentrations may reflect central nervous system activity of parent amines, these data suggest a relationship between depression and decreased dopaminergic and serotonergic activity.

A comparison of the gas chromatographic and mass spectrometric properties of the pentafluoropropionyl and heptafluorobutyryl derivatives of the methyl, trifluoroethyl, pentafluoropropyl and hexafluoroisopropyl esters of twelve acidic metabolites of biogenic amines

The gas chromatographic and mass spectrometric properties of the methyl, trifluoroethyl, pentafluoropropyl and hexafluoroisopropyl esters of the pentafluoropropionyl and heptafluorobutyryl derivatives of twelve important acidic metabolites of biogenic amines have been investigated. The optimum derivatization conditions for the different classes of metabolites have been established and the byproducts formed in some of the derivatizations have been identified. Under certain derivatizing conditions, back-exchange of deuterium in the labelled internal standards was observed. No single derivative appears to be ideally suitable for the simultaneous quantitative analysis by GC/MS of all twelve metabolites, so extracts of plasma and urine were split and a combination of the methyl or trifluoroethyl esters of the pentafluoropropionyl derivatives were used.

Simultaneous analysis of twelve biogenic amine metabolites in plasma, cerebrospinal fluid and urine by capillary column gas chromatography-high-resolution mass spectrometry with selected-ion monitoring

A procedure is described for the simultaneous determination of twelve acidic and alcoholic metabolites of trace and catecholic biogenic amines in plasma, cerebrospinal fluid and urine by capillary column gas chromatography--high-resolution mass spectrometry. Protein precipitation with sulphosalicylic acid, derivatization with two different reagent systems, final sample clean-up with a buffer wash and a program for automatically changing the reference mass of the mass spectrometer to suit each group of compounds as they are eluted from the column, are the main novel features of the procedure. A brief description of the synthesis of the deuterium-labelled internal standards is provided. The procedure is applied to biological samples and a comparison to reported values is given.

Determination of dihydroxyphenylalanine and dihydroxyphenylacetic acid in biological samples by coupled-column liquid chromatography with dual coulometric—amperometric detection

Adrenaline, noradrenaline, dopamine and dihydroxyphenylalanine in brain tissue and dihydroxyphenylacetic acid in plasma have been determined by direct injection of brain homogenates or plasma into a liquid chromatographic system comprising three columns, one packed with a boronic acid gel and two with reversed-phase material. The catecholamines and dihydroxyphenylalanine were selectively adsorbed on the boronic acid gel and separated by ion-pair chromatography on the reversed-phase columns. DOPAC was determined in a modified system without the addition of ion-pairing reagents. The catechols were detected by coulometry or amperometry with two working electrodes, operated in the oxidative-reductive mode. The reductive signal was used for quantification. The limits of determination were 0.05 nmol g(-1) with 40 mg brain tissue and 2 nmol 1(-1) with 0.5 ml plasma for DOPA and DOPAC respectively. The limit of quantification of DA and DOPAC in urine was about 0.1 micromol l(-1).

Serotonin and schizophrenia: correlations between serotonergic activity and schizophrenic motor behavior

Increased serotonergic activity in animals has been associated with a variety of stereotyped motor behaviors. In addition, serotonin facilitates brainstem, reticular, and spinal motor neuronal activity implicated in the expression of these behaviors. This report presents positive correlations between both peripheral (platelet serotonin levels) and central (cerebrospinal concentrations of 5-hydroxy-indoleacetic acid) measures of serotonin metabolism and the symptom of peculiar or unusual mannerisms and posturing in schizophrenic patients. The findings are discussed in light of the animal behavioral correlates of increased serotonergic activity and the stereotyped affectomotor behavior seen in some schizophrenic patients.

Quantification of a number of biogenic amines and their metabolites in brain homogenates by gas chromatography--mass spectrometry

A sensitive method is described for the assay of various biogenic amines and their metabolites from brain tissue homogenates. Based on gas chromatography-mass spectrometry and selected ion monitoring, the method allows reliable low-level quantification of the compounds of interest. By careful study of reaction conditions both in the preparation of derivatives for gas chromatography and in the synthesis of deuterated analogues for internal standard use, relatively simple procedures could be applied with good analytical efficiency. Correlation of the results with those obtained by a high-performance liquid chromatographic procedure was also investigated, and a neurologic application of the method is briefly discussed.

Cerebrospinal fluid monoamine metabolites in narcolepsy and hypersomnia

Two groups of patients with the common complaint of excessive daytime sleepiness were examined. One group fulfilled the criteria for narcolepsy. The other had the sole symptom of excessive daytime sleepiness, confirmed by sleep latency tests, which was unaccompanied by systemic illness. Spinal fluid examinations for homovanillic acid, 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylethylene glycol, and 5-hydroxyindoleacetic acid were carried out before and after administration of probenecid on the 20 patients and 40 controls. Probenecid-corrected accumulation of the dopamine metabolites was significantly increased in each of the patient groups, suggesting an association between pathological sleepiness and elevated dopamine turnover in the central nervous system.

REM sleep eye movement activity and CSF concentrations of 5-hydroxyindoleacetic acid in psychiatric patients

The relationship between rapid-eye-movement (REM) sleep tonic and phasic activity measures and the pre- and postprobenecid cerebrospinal fluid (CSF) concentrations of the serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) was examined in a sample of 14 unmedicated psychiatric patients. The average duration of an eye movement burst and the average number of eye movements within a burst were found to be inversely related to the probenecid corrected accumulation of 5-HIAA in the CSF. These results are interpreted as indicating an association between REM burst eye movement activity and serotonin turnover in psychiatric subjects.

Monoamine metabolite concentrations in the cerebrospinal fluid of normal and narcoleptic dogs

Because of the similarity between human and canine narcolepsy, an animal model has emerged with which to investigate the neurochemical basis of the disease. In this study, in vivo differences in cerebral neurotransmitter function between normal and affected dogs were measured by comparing, before and after probenecid administration, the concentrations in cisternal cerebrospinal fluid of the monoamine metabolites 5-hydroxyindoleacetic acid, homovanillic acid, 3,4-dihydroxyphenylacetic acid, and 3-methoxy-4-hydroxyphenylethylene glycol. Cisternal cerebrospinal fluid was collected from the cisterna magna of anaesthetized animals, and samples were analyzed for the metabolites and probenecid using combined gas chromatography-mass spectrometry. The concentrations of both the conjugated and non-conjugated forms of each of the metabolites were determined in all samples and the role of conjugation in cerebral monoamine metabolism is discussed. Before probenecid treatment, comparisons of metabolite concentrations in samples from normal versus narcoleptic dogs showed significantly lower amounts of the dopamine and of the 5-hydroxytryptamine metabolites in CSF from the affected animals. After probenecid administration, the concentrations in the CSF of all the metabolites increased. However, the amounts of 5-hydroxyindoleacetic acid, and the norepinephrine metabolite 3-methoxy-4-hydroxyphenylethylene glycol, in samples from narcoleptic dogs were significantly lower than those found in samples from normal dogs. The implications of these results for our understanding of the neurochemical basis of REM sleep initiation and for treatment of narcolepsy/cataplexy are discussed.

Simultaneous determination of 3,4-dihydroxyphenylalanine, 5-hydroxytryptophan, dopamine, 4-hydroxy-3-methoxyphenylalanine, norepinephrine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, serotonin, and 5-hydroxyindoleacetic acid in rat cerebrospinal fluid and brain by high-performance liquid chromatography with electrochemical detection

A method using reversed-phase ion-pair high-performance liquid chromatography with electrochemical detection for the simultaneous determination of tryptophan (TRP), 3,4-dihydroxyphenylalanine (DOPA), and their metabolites in whole brain, small-brain parts, and cerebrospinal fluid of rats has been developed. The sample preparation requires only homogenization in perchloric acid and centrifugation before injection onto the column. With a LiChrosorb RP-18 (10 micrometer) column and a mobile phase consisting of a phosphate (NaH2PO4, 0.1 M)-methanol mixture with octylsulfonate (2.6 x 10(-3) M) at pH 3.35 and 26 degrees C, the separation of DOPA, dopamine, norepinephrine, 3,4-dihydroxyphenylacetic acid, homovanillic acid, 4-hydroxy-3-methoxyphenylalanine, TRP, 5-hydroxytryptophan (5-HTP), serotonin, and 5-hydroxyindoleacetic acid was achieved. The method has been applied to study the effect of alpha-monofluoromethyldopa alone and in combination with L-DOPA or L-5-HTP, on the catechol and 5-OH indole levels in brain and CSF of the rat.

Gas chromatographic method for the simultaneous determination of dopamine and norepinephrine metabolites

A new gas chromatographic method, using only flame ionization detection which can determine nanogram quantities of homovanillic acid, 3,4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylethyleneglycol and 3,4-dihydroxyphenylethyleneglycol in the same reaction, is described. These compounds are treated with diazoethane and n-butylboronic acid. Homovanillic acid and 3,4-dihydroxyphenylacetic acid are converted to their ethyl esters while 3-methoxy-4-hydroxyphenylethyleneglycol and 3,4-dihydroxyphenylethyleneglycol form cyclic boronates and are thus assayed. This method is quantitative, highly specific and sensitive. It has been applied to the analysis of these compounds in urine.

Quantitative determination of 3-methoxy-4-hydroxyphenylethyleneglycol and its sulfate conjugate in human lumbar cerebrospinal fluid using liquid chromatography with amperometric detection

A sensitive and direct reversed-phase liquid chromatographic method with amperometric detection was developed for the determination of 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG). The concentrations of the free and sulfate conjugate of MHPG were measured in human lumbar cerebrospinal fluid. All samples were preconcentrated by extraction with ethyl acetate. Deconjugation of the sulfate form of MHPG was achieved by enzymatic hydrolysis with sulfatase. Peaks were identified on the basis of chromatographic behavior, ratio of responses at several oxidation potentials and the stopped-flow UV spectra of the collected fractions. The free MHPG content of 20 cerebrospinal fluid samples ranged between 0.720 and 19.51 ng/ml with the mean of 5.126 +/- 4.652 (S.D.) ng/ml. The sulfate conjugate of MHPG in 12 samples of cerebrospinal fluid ranged between 0.08 and 0.850 ng/ml with the mean value of 0.2365 +/- 0.2269 (S.D.) ng/ml. Although our results correlate well with the literature values, no attempt was made to interpret the quantitative data since samples were obtained from routine, diagnostic testing of patients admitted to the medical or neurologic services at the Mount Sinai Hospital.

Alterations in cerebrospinal fluid dopamine metabolites following physostigmine infusion

The effect of IV physostigmine administration on the cerebrospinal fluid (CSF) levels of homovanillic acid (HVA) and dihydroxyphenylacetic acid (DOPAC) in normal subjects was determined. After an adjustment for differing CSF concentrations of probenecid, physostigmine was found to elevate CSF HVA and DOPAC concentrations. The authors discuss these changes in CSF HVA and DOPAC and their possible relationship to the ability of physostigmine to decrease the symptoms of some patients with tardive dyskinesia.