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Objective: To investigate neuroinflammation in Parkinson's disease (PD) with [ 11 C]PBR28 positron emission tomography (PET) and cerebrospinal fluid (CSF) biomarkers, and the relationship to dopaminergic functioning measured with 6-[ 18 F]-fluoro-L-dopa ([ 18 F]FDOPA) PET., Methods: The clinical cohort consisted of 20 subjects with PD and 51 healthy controls (HC). All HC and 15 PD participants underwent [ 11 C]PBR28 High Resolution Research Tomograph (HRRT) PET for the quantitative assessment of cerebral binding to the translocator protein (TSPO), a neuroinflammation marker. CSF samples were available from 17 subjects with PD and 21 HC and were examined for soluble triggering receptor expressed on myeloid cells 2 (sTREM2), chitinase 3-like 1 protein (YKL-40), neurogranin (NG), alpha-synuclein (aSyn) and oligo-alpha-synuclein. All subjects with PD underwent [ 18 F]FDOPA HRRT PET., Results: While the subjects with PD and HC did not differ in the total volume of distribution (V T ) of [ 11 C]PBR28 in any studied brain regions, higher levels of neuroinflammation and neurodegeneration CSF biomarkers sTREM2 and NG, respectively were associated with more severe motor symptoms evaluated by The Unified Parkinson's Disease Rating Scale motor part (UPDRS-III) (r = 0.52, p = 0.041 and r = 0.59, p = 0.016 respectively). Additionally, in the PD group increased [ 11 C]PBR28 V T in the basal ganglia and substantia nigra (SN) was related to higher levels of neuroinflammation biomarker YKL-40 (p < 0.01)., Conclusion: Associations between CSF biomarkers, motor disability and [ 11 C]PBR28 V T in the striatum and SN may support a role for neuroinflammation in PD., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Haidar Al-Abdulrasul reports financial support was provided by Finnish Parkinson Foundation. Riikka Ajalin reports financial support was provided by Finnish Parkinson Foundation. Anna Bruck reports financial support was provided by Finnish Parkinson Foundation. Haidar Al-Abdulrasul reports financial support was provided by Helsinki University research funds. Anna Bruck reports financial support was provided by Finnish State Research Funding (VTR). Henrik Zetterberg reports a relationship with Swedish Research Council (2018 02532) that includes: funding grants. Henrik Zetterberg reports a relationship with The European Research Council (681 712) that includes: funding grants. Henrik Zetterberg reports a relationship with Swedish State Support for Clinical Research (ALFGBG 720931) that includes: funding grants. Henrik Zetterberg reports a relationship with the Alzheimer Drug Discovery Foundation (ADDF), USA (201 809 2016862) that includes: funding grants. Henrik Zetterberg reports a relationship with The AD Strategic Fund and the Alzheimer's Association (ADSF 21 831376C, ADSF 21 831381 C and ADSF 21 831377 C) that includes: funding grants. Henrik Zetterberg reports a relationship with the Olav Thon Foundation that includes: funding grants. Henrik Zetterberg reports a relationship with The Erling-Persson Family Foundation that includes: funding grants. Henrik Zetterberg reports a relationship with Stiftelsen för Gamla Tjänarinnor, Hjärnfonden, Sweden (FO2019 0228) that includes: funding grants. Henrik Zetterberg reports a relationship with The European Union's Horizon 2020 research and innovation programme under the Marie Sktodowska Curie grant agreement No 860197 (MIRIADE) that includes: funding grants. Henrik Zetterberg reports a relationship with European Union Joint Program for Neurodegenerative Disorders (JPND2021 00694) that includes: funding grants. Henrik Zetterberg reports a relationship with the UK Dementia Research Institute at UCL that includes: funding grants. Kaj Blennow reports a relationship with Swedish Research Council (2017 00915) that includes: funding grants. Kaj Blennow reports a relationship with the Alzheimer Drug Discovery Foundation (ADDF), USA (RDAPB 201809 2016615) that includes: funding grants. Kaj Blennow reports a relationship with the Swedish Alzheimer Foundation (AF 742 881) that includes: funding grants. Kaj Blennow reports a relationship with Hjärnfonden, Sweden (FO2017 0243) that includes: funding grants. Kaj Blennow reports a relationship with the Swedish state under the agreement between the Swedish government and the County Councils, the ALF-agreement (ALFGBG 715986) that includes: funding grants. Kaj Blennow reports a relationship with European Union Joint Program for Neurodegenerative Disorders (JPND2019 466 236) that includes: funding grants. Kaj Blennow reports a relationship with The Alzheimer's Association 2021 Zenith Award (ZEN 21 848495). that includes: funding grants. Laura Ekblad reports a relationship with Emil Aaltonen Foundation that includes: funding grants. Juha Rinne reports a relationship with Academy of Finland research grants (310 962) that includes: funding grants. Juha Rinne reports a relationship with the Sigrid Juselius Foundation that includes: funding grants. Juha Rinne reports a relationship with Finnish State Research Funding (VTR) that includes: funding grants. Henrik Zetterberg has served at scientific advisory boards and/or as a consultant for Abbvie, Alector, Annexon, Artery Therapeutics, AZTherapies, CogRx, Denali, Eisai, Nervgen, Pinteon Therapeutics, Red Abbey Labs, Passage Bio, Roche, Samumed, Siemens Healthineers, Triplet Therapeutics, and Wave, has given lectures in symposia sponsored by Cellectricon, Fujirebio, Alzecure, Biogen, and Roche, and is a co-founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Program (outside submitted work). Kaj Blennow has served as a consultant, at advisory boards, or at data monitoring committees for Abcam, Axon, BioArctic, Biogen, Julius Clinical, Lilly, MagQu, Novartis, Roche Diagnostics, and Siemens Healthineers, and is a co-founder of Brain Biomarker Solutions in Gothenburg AB (BBS), which is a part of the GU Ventures Incubator Program (outside submitted work). Juha Rinne serves as a consultant neurologist for Clincal Research Services Turku (CRST) and as a member of data monitoring board (Lundbeck) and global expert panel (Novo Nordisk). If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: We describe a new method for simultaneous measurement of monoamine metabolites (3-O-methyldopa [3-OMD], 3-methoxy-4-hydroxyphenylethyleneglycol [MHPG], 5-hydroxyindoleacetic acid [5-HIAA], and homovanillic acid [HVA]) and 5-methyltetrahydrofolate (5-MTHF) and its use on cerebrospinal fluid (CSF) samples from pediatric patients., Methods: Monoamine metabolites and 5-MTHF were measured by high-performance liquid chromatography with fluorescence detection. CSF samples were prospectively collected from children according to a standardized collection protocol in which the first 1-ml fraction was used for analysis., Results: Monoamine metabolites and 5-MTHF were separated within 10min. They showed linearity from the limit of detection to 1024nmol/l. The limit of quantification of each metabolite was sufficiently low for the CSF sample assay. In 42 CSF samples after excluding cases with possibly altered neurotransmitter profiles, the concentrations of 3-OMD, MHPG, 5-HIAA, HVA, and 5-MTHF showed significant age dependence and their ranges were comparable with the reference values in the literature. The metabolite profiles of aromatic l-amino acid decarboxylase deficiency, Segawa disease, and folate receptor α defect by this method were compatible with those in the literature., Conclusions: This method is a simple means of measuring CSF monoamine metabolites and 5-MTHF, and is especially useful for laboratories not equipped with electrochemical detectors., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Background: Subarachnoid hemorrhage (SAH) has been associated with pronounced acute sympathetic activation. The purpose of this investigation is to identify demographic, clinical, radiological, and anatomical features of SAH that relate to sympathetic activation., Methods: Observational study of consecutive Grades 3-5 SAH patients requiring ventriculostomy and undergoing endovascular aneurysmal obliteration. All patients underwent cerebrospinal fluid (CSF) sampling within 48 h of SAH onset, and samples were assayed for various catecholamine compounds and metabolites. Univariate analyses were performed to identify variables associated with catecholamine levels, and to correlate linearity among catecholamine compounds and metabolites. Variables demonstrating a possible association and variables of interest were entered into linear regression models to determine predictors of catecholamine elevations., Results: Of the 102 patients, mean age was 58 years and 74% were female; 42% were Hunt-Hess (H/H) grade 4/5, 61% had a computed tomography (CT) score of 3/4, 57% had anterior cerebral or communicating artery (ACA/ACom) aneursysms, and 23% had aneurysms in the posterior circulation. In the univariate analysis, age, gender, H/H grade, CT score, and aneurysm location demonstrated various associations with catecholamine levels, and substantial positive correlations existed between the various catecholamine compounds and metabolites. Linear regression analyses revealed H/H grade to be an independent predictor of elevated CSF epinephrine (EPI), 3,4-dihydroxyphenylalanine (DOPA) and 3,4-dihydroxyphenyl acetic acid (DOPAC) levels, and of the norepinephrine/3,4-dihydroxyphenylglycol (NE/DHPG) ratio (p < 0.05 for all analyses). Female gender independently predicted increased dopamine (DA) and DOPAC levels (p < 0.05 for two analyses), as well as possibly DOPA levels (p < 0.1). Age, CT score and aneurysm location demonstrated only inconsistent associations and trends., Conclusions: Central sympathetic activation relates to clinical severity and female gender. No definitive associations were found for age, hemorrhage amount, or aneurysm location.

Background: Patients experiencing apoplectic intracranial processes may develop neurogenic cardiomyopathy (NC). The purpose of this research is to determine whether cerebrospinal fluid (CSF) catecholamine levels are elevated in subarachnoid hemorrhage (SAH) patients with NC when compared to those without NC., Methods: Observational study of consecutive grades 3-5 SAH patients requiring ventriculostomy. All patients underwent CSF sampling for catecholamine levels, and transthoracic echocardiography (TTE) to assess for NC, within 48 h of SAH onset. Univariate analyses were performed to identify clinical and laboratory variables associated with NC. Clinical variables associated with NC in the univariate analysis were entered into logistic regression models along with the candidate catecholamine variables to identify predictors of NC., Results: The study group contained 100 patients--mean age of study subjects was 58 years, 73% were female, and 15% developed NC. NC patients were more likely to have a worse clinical grade than patients without NC (80 vs. 34%, P = 0.001). NC patients possessed greater DOPA levels (5.83 vs. 4.60 nmol/l, P = 0.044), and a trend toward greater noradrenergic activity as determined by NE/DHPG ratio (0.3799 vs. 0.2519, P = 0.073). Multivariate analysis identified worse clinical grade (OR 7.09, P = 0.005) and possibly NE levels (OR 1.005, P = 0.057) as independent predictors of NC. Bivariate analysis reinforced the findings for NE (OR 1.006, P = 0.022), and also identified DOPA levels (OR 1.001, P = 0.034) and NE/DHPG (OR 22.18, P = 0.019) as predictors of NC., Conclusions: SAH patients with NC tend to have greater CSF catecholamine levels than those without NC. However, the development of NC may also be related to factors not evaluated by our study.

We present the clinical, biochemical, and molecular findings of three Greek patients with tyrosine hydroxylase (TH) deficiency. All patients presented with a severe clinical phenotype characterized by prominent motor delay, infantile parkinsonism, oculogyric crises, and signs of autonomic dysfunction. Cerebrospinal fluid analysis disclosed reduced dopamine metabolites and normal pterins. Response to levodopa was favorable though not dramatic. All patients were homozygous for a previously reported mutation (p.L236P). SNP haplotype analysis was consistent with a common ancestral mutation, thus indicating a founder effect in Greek patients with TH deficiency., ((c) 2010 Movement Disorder Society.)

Background: Abnormally high CSF 3-OMD occurs frequently for RLS patients indicating either increased l-dopa synthesis, limitations in l-dopa decarboxylation or increased MAT/COMT activity, or some combination of these. Increased tyrosine hydroxylase activity was found on both the RLS autopsy and the rodent iron-deprivation model of RLS, suggesting increased DA synthesis in RLS. We, therefore, hypothesized elevated 3-OMD in RLS results from increased DA synthesis and that this should occur accordingly with increased HVA. It would then also reflect both the more severe iron insufficiency pathology of RLS and greater clinical severity, shown by the objective measure of PLMS/hr., Methods: Patients off RLS medications and matched controls had lumbar punctures at either 10 a.m. or 10 p.m.; RLS patients were grouped by normal or abnormally high 3-OMD (>10 nmol/l)., Results: Forty-nine RLS patients (30 high, 19 normal 3-OMD) and 36 age- and gender-matched controls, analyzed separately by time of CSF collection, did not significantly differ in age or gender. RLS patients with high 3-OMD had significantly higher CSF HVA, while those with normal 3-OMD had consistently lower CSF HVA than controls. CSF ferritin was consistently lower compared to controls for the high 3-OMD but not the normal 3-OMD RLS patients. The PLMS/hr was significantly higher for RLS patients with high compared to normal 3-OMD, indicating high 3-OMD patients had more severe RLS., Conclusions: Abnormal elevation in 3-OMD for RLS patients may reflect increased dopamine synthesis for more severe but perhaps not mild RLS. These differences in the putative dopamine pathology of RLS may indicate different phases or expression of RLS biology or different underlying disease processes.

Objective: Biomarkers are increasingly important to diagnose and test treatments of neurodegenerative diseases such as Parkinson disease (PD). This study compared neuroimaging, neurochemical, and olfactory potential biomarkers to detect central dopamine (DA) deficiency and distinguish PD from multiple system atrophy (MSA)., Methods: In 77 PD, 57 MSA, and 87 control subjects, radioactivity concentrations in the putamen (PUT), caudate (CAU), occipital cortex (OCC), and substantia nigra (SN) were measured 2h after 6-[18F]fluorodopa injection, septal myocardial radioactivity measured 8min after 6-[18F]fluorodopamine injection, CSF and plasma catechols assayed, or olfaction tested (University of Pennsylvania Smell Identification Test (UPSIT)). Receiver operating characteristic curves were constructed, showing test sensitivities at given specificities., Results: PUT:OCC, CAU:OCC, and SN:OCC ratios of 6-[18F]fluorodopa-derived radioactivity were similarly low in PD and MSA (p<0.0001, p<0.0001, p=0.003 compared to controls), as were CSF dihydroxyphenylacetic acid (DOPAC) and DOPA concentrations (p<0.0001, each). PUT:SN and PUT:CAU ratios were lower in PD than in MSA (p=0.004; p=0.005). CSF DOPAC correlated positively with PUT:OCC ratios (r=0.61, p<0.0001). Myocardial 6-[18F]fluorodopamine-derived radioactivity distinguished PD from MSA (83% sensitivity at 80% specificity, 100% sensitivity among patients with neurogenic orthostatic hypotension). Only PD patients were anosmic; only MSA patients had normal olfaction (61% sensitivity at 80% specificity)., Conclusions: PD and MSA feature low PUT:OCC ratios of 6-[18F]fluorodopa-derived radioactivity and low CSF DOPAC and DOPA concentrations, cross-validating the neuroimaging and neurochemical approaches but not distinguishing the diseases. PUT:SN and PUT:CAU ratios of 6-[18F]fluorodopa-derived radioactivity, cardiac 6-[18F]fluorodopamine-derived radioactivity, and olfactory testing separate PD from MSA.

Objective: Pure autonomic failure (PAF) and Parkinson's disease (PD) share several clinical laboratory abnormalities; however, PAF is not associated with parkinsonism. In this study, we tested the hypothesis that preservation of nigrostriatal dopaminergic innervation explains the absence of motor dysfunction in PAF. MMETHODS: Patients with PAF (N = 5) or PD (N = 21) and control subjects (N= 14) had brain 6-[18F]fluorodopa positron emission tomographic scanning and cerebrospinal fluid catechol measurements. A patient with PAF and another with PD had rapid postmortem striatal, nigral, and sympathetic ganglion sampling, with assays of catechols and tyrosine hydroxylase activity., Results: The PAF and PD groups had similarly low mean substantia nigra (SN):occipital (OCC) ratios of 6-[18F]fluorodopa-derived radioactivity and similarly low cerebrospinal fluid dihydroxyphenylacetic acid and DOPA levels. Only the PD group, however, had low PUT:OCC, caudate:OCC, or PUT:SN ratios. The PAF and PD cases had similarly low SN tissue concentrations of dopamine and tyrosine hydroxylase activity, but the PD patient had tenfold lower PUT dopamine and the PAF patient 15-fold lower myocardial norepinephrine concentrations., Conclusions: Surprisingly, PAF and PD entail similarly severe nigral and overall central dopaminergic denervation. There is more severe loss of striatal dopaminergic terminals in PD than in PAF and more severe loss of sympathetic noradrenergic terminals in PAF than in PD. These differences explain the distinctive clinical manifestations of the two Lewy body diseases. Parkinsonism appears to reflect striatal dopamine deficiency rather than loss of nigral dopaminergic neurons per se.

Background: High cerebrospinal fluid (CSF) norepinephrine (NE) concentrations in aging and Alzheimer's disease (AD) could reflect decreased NE clearance from central nervous system (CNS) extracellular fluid or increased release of NE into CNS extracellular fluid. Measuring CSF concentrations of the intraneuronal NE metabolite dihydroxyphenylglycol (DHPG), an estimate of NE clearance, and the NE precursor dihydroxyphenylacetic acid (DOPA), an estimate of NE biosynthesis, can help differentiate these mechanisms., Methods: NE, DHPG, and DOPA were determined by HPLC in CSF and plasma obtained following yohimbine, clonidine, and placebo. Ten AD, 10 older, and 11 young subjects were studied., Results: CSF DOPA following yohimbine was higher in older and AD than in young subjects. CSF DHPG did not differ among groups. Plasma DOPA following yohimbine was higher in AD than in young subjects., Conclusions: During alpha-2 adrenoreceptor blockade in both aging and AD, there are increased responses of CNS NE biosynthesis and release with unchanged CNS NE clearance. This pattern is consistent with partial loss of CNS noradrenergic neurons with compensatory activation of remaining CNS noradrenergic neurons. Given the marked loss of locus coeruleus (LC) noradrenergic neurons in AD, achievement of high CSF NE suggests particularly prominent compensatory activation of remaining LC neurons in this disorder.

Children with the opsoclonus-myoclonus syndrome (OMS) usually respond to corticotropin (adrenocorticotrophic hormone, ACTH) treatment but the mechanism of benefit is unknown. We previously showed that both cerebrospinal fluid (CSF) homovanillic acid (HVA) and 5-hydroxyindole-acetic acid (5-HIAA) concentrations are low in pediatric OMS. In this study, we measured levels of CSF Dopa, catecholamines, deaminated metabolites of catecholamines, as well as HVA and 5-HIAA in eight patients before and during treatment with ACTH. All the children were ACTH-responsive with 50-70% improvement in multiple clinical features of OMS. ACTH treatment reduced the HVA concentration in every child by a mean of 21% (p < 0.001). Treatment with ACTH was associated with significant correlations between dopaminergic markers such as HVA, dihydroxyphenylacetic acid (DOPAC), and Dopa. There were no significant changes in the CSF concentrations of the noradrenergic markers norepinephrine (NE) and dihydroxyphenylglycol (DHPG), or the serotonergic marker 5-HIAA. The only child with a marked inflammatory pattern in CSF, which was reversed by ACTH, was atypical for a large increase in NE and decrease in 5-HIAA during ACTH treatment. Beneficial effects of ACTH in OMS are not associated with normalization of HVA or 5-HIAA levels. The pattern of decreased HVA and unchanged DOPAC levels could reflect decreased extraneuronal uptake of catecholamines (which steroids inhibit) or decreased 0-methylation of catecholamines in nonneuronal cells.

Objective: To investigate endogenous cerebrospinal fluid catecholamines in Parkinson's disease., Material and Methods: Basal concentrations of free norepinephrine (NE), dopamine (DA), epinephrine (E), 3,4-dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylalanine (DOPA) in cerebrospinal fluid (csf) and plasma were measured using reverse-phase HPLC with electrochemical detection in 16 patients with Parkinson's disease and 21 control patients with low back pain., Results: Parkinsonian patients had significantly decreased values of csf NE and DOPAC, the strong relationship between plasma and csf NE was disrupted and neither was there any age related increase of plasma NE. In l-DOPA treated patients plasma DA and DOPA concentrations were raised and csf DOPAC values were inversely related to severity of disease (Hoehn and Yahr score). Csf E concentrations were also reduced in parkinsonian patients whereas csf DA concentrations were unchanged. Csf DOPA concentrations were insignificantly decreased in parkinsonian patients., Conclusions: These results point towards a diffuse neuronal dysfunction in Parkinson's disease and indicate that lumbar csf NE and csf DOPAC are of central nervous origin.

We have found mutations in the Menkes disease gene (MNK) which impair, but do not abolish, correct mRNA splicing in patients with less severe clinical phenotypes. In one family, four males aged 2-36 years with a distinctive Menkes variant have a mutation at the +3 position of a splice donor site near the 3' end of the Menkes coding sequence that is associated with exon skipping and a stable mutant transcript. In an unrelated 15-year-old male with typical occipital horn syndrome, a point mutation at the -2 exonic position of a splice donor site in the middle of the gene causes exon-skipping and activation of a cryptic splice acceptor site. In both mutations, maintenance of some normal splicing is demonstrable by RT-PCR, cDNA sequencing and ribonuclease protection.

The transport of L-6-fluorodopa and its major metabolites from the blood to the brain, cerebrospinal fluid (CSF), and muscle was studied in carbidopa-pretreated cynomolgus monkeys. A bolus intravenous injection of 18F-L-6-fluorodopa was followed by serial positron emission tomography scans and sampling of cisternal CSF and arterial blood. The relative concentrations of L-6-fluorodopa and its metabolites were determined in blood plasma and CSF by high-performance liquid chromatography. Raising the blood concentration of phenylalanine by intraperitoneal injection markedly reduced the accumulation of tracer in the brain. This indicates that L-6-fluorodopa and 3-O-methylfluorodopa, like native L-dopa and its O-methylated derivative, are transported at the brain capillary by the large neutral amino acid carrier-mediated system, which is subject to saturation and competition by other large neutral amino acids (such as phenylalanine) at physiological plasma concentrations. In contrast, administration of phenylalanine had no effect on the accumulation of tracer either in muscle, or as L-6-fluorodopa and 3-O-methylfluorodopa, in CSF. This suggests that the transport of L-dopa and its derivatives at the blood-CSF barrier differs from the transport at the blood-brain barrier and also that measurement of CSF L-dopa is not a good index of the transport and pharmacokinetics of L-dopa in the brain. However, the effect of phenylalanine administration in reducing the concentration of fluorohomovanillic acid in the CSF suggests that the concentration of homovanillic acid in the CSF is an accurate reflection of dopamine turnover in the brain.

We measured CSF and serum concentrations of monoamines and monoamine metabolites in normal control subjects and in patients with partial epilepsy between and less than 2 h after complex partial seizures (CPS) or secondarily generalized tonic-clonic seizures (SGTCs). After SGTCs, concentrations of norepinephrine in CSF were significantly higher (p less than 0.05) than interictal concentrations, concentrations after PSs, and concentrations in control subjects. Serum epinephrine levels also were significantly higher after SGTCs than interictal and control subjects' levels. CSF HVA levels were significantly higher after PSs than interictal or control subjects' levels. CSF concentrations of norepinephrine and its intraneuronal metabolite, dihydroxyphenylglycol, were highly correlated, both interictally and following SGTCs, whereas correlations between serum and CSF levels of these catechols generally were not statistically significant. The results indicate that seizures are associated with release of catecholamines in the central nervous system.

We determined the concentrations of tyrosine, L-3,4-dihydroxyphenylalanine (DOPA), dopamine (DA), and 3-O-methyldopa (3-OMD) in the cerebrospinal fluid (CSF) of parkinsonian patients and elevated potential interactions between the substances. We found a significant increase in tyrosine, and a significant decrease in DOPA, DA, and 3-OMD. We also found that for a given concentration of DOPA, DA and 3-OMD were proportional. In addition, the ratio of DA to 3-OMD was significantly shifted in favor of DA in parkinsonian patients.

We have established HPLC assay conditions that could measure the levels of 14 monoamines and their metabolites simultaneously. Monoamine levels in cerebrospinal fluids of 12 Chinese patients with Alzheimer's disease were compared with those in samples from patients with benign prostate hyperplasia. Of the 14 monoamines and metabolites, only three were found to be present in all samples. Although the levels of 5-hydroxy-3-indoleacetic acid (HIAA) and homovanillic acid (HVA) in cerebrospinal fluid of patients with Alzheimer's disease were lower, and the levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) higher, as compared to control patients, no significant differences were found between these two groups.

1. The effects of levodopa alone (50 mg kg-1) and levodopa (10 mg kg-1) plus benserazide (50 mg kg-1) were tested on the levels of dopa, dopamine, 3-methoxytyrosine (3-MT), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), measured by h.p.l.c. with electrochemical detection, in samples of plasma, CSF, urine, striatum and hypothalamus of rats taken 30 min after injection. Levodopa plus benserazide produced significantly higher levels of dopa in plasma and brain than levodopa alone and reduced the peripheral synthesis and metabolism of dopamine. 2. When given chronically over 6 weeks the advantages of adding benserazide (50 mg kg-1 day-1) to levodopa (40 mg kg-1 day-1) were less marked and although more dopamine was present in the striatum than with levodopa given alone (200 mg kg-1 day-1) there was no evidence of any increase in its metabolites (HVA and DOPAC) and therefore of its turnover and utilisation. 3. The most striking effect of chronic treatment with levodopa plus benserazide was the appearance of large quantities of 3-MT in plasma, CSF and brain. 4. When levodopa alone, or levodopa plus benserazide, was given as an acute challenge to animals receiving the same treatment chronically, it was found that levodopa alone still produced increases in striatal dopamine, DOPAC and HVA in those animals dosed chronically on levodopa, but it was less effective in this respect when given with benserazide to the animals dosed with levodopa plus benserazide. 5. It is concluded that this difference in levodopa distribution may depend on the persistence in benserazide-treated animals of 3-MT, which has a long half-life and may compete with dopa for transport into the blood and brain. 6. The implication of these findings to the treatment of Parkinsonism is discussed.

Blood plasma samples from 60 neuroblastoma patients prior to, during, and following treatment were studied for their content of circulating DOPA using a radioenzymatic assay. Normal values were established from children who were tumor-free or had other nonneurogenic tumors. The highest plasma DOPA concentration in tumor-free or nonneuroblastoma controls was 5.3 ng/ml with a mean of 2.15 ng/ml. Most neuroblastoma patients (28/31) with active disease had DOPA values above this level. Only one out of 30 "successfully" treated patients without evidence of disease was encountered with an abnormally high level. In treated patients, elevated values forewarned of impending clinical recurrence or persistent tumor. Cerebrospinal fluid DOPA levels in one patient with cerebral neuroblastoma were extraordinarily high and suggests that this assay may prove useful to distinguish neuroblastoma from other central neuroectodermal or metastatic tumors. Plasma DOPA appears to be a reliable predictive and diagnostic test for neuroblastoma.

Catecholamines and indolealkylamines are of clinical interest in neurological and psychiatric disorders. We measured 3-methoxy-DOPA, 3-methoxy-4-hydroxyphenylglycol, dihydroxyphenylacetic acid, tryptophan, 5-hydroxyindoleacetic acid and homovanillic acid in human cerebrospinal fluid with a simple, sensitive , inexpensive, rapid and accurate procedure using high performance liquid chromatography coupled to an electrochemical detector. Patients with Parkinson's disease have a decrement in homovanillic acid that is reversed by treatment with L-3,4-dihydroxyphenylalanine. After this medication, 3-methoxy-DOPA is measurable in cerebrospinal fluid. Patients with depression show a decrease in serotonin turnover expressed by diminished 5-hydroxyindoleacetic acid content in cerebrospinal fluid. Depressed patients also show low levels of tryptophan. Monoamine metabolites are augmented in patients with subarachnoid hemorrhage.

L-3-(3,4-Dihydroxyphenyl)alanine (DOPA) and its 3-O-methyl metabolite (OMD) were measured in plasma and cerebrospinal fluid by a new assay which combines N,O-acetylation of amino acids in aqueous media, preparation of pentafluorobenzyl esters under anhydrous conditions, and analysis by gas chromatography-electron capture negative ion mass spectrometry. The N,O-acetyl, carboxy-PFB derivatives gave abundant carboxylate anions ([M-CH2C6F5]-) which were suitable for sensitive analysis using selected ion monitoring. Plasma and CSF samples were sufficiently purified by a simple organic solvent extraction. Analytical recovery for DOPA was 100.2 +/- 3.7% at the level of 100 nmol/l. Analysis of DOPA in plasma was performed with a relative standard deviation of 5%. The limit of quantitation in plasma and CSF was at the sub-nmol/l level. In healthy adults, DOPA concentration in plasma was 9.0 +/- 2 nmol/l (n = 11) and in CSF 3.5 +/- 0.9 nmol/l (n = 9). The concentration of OMD in plasma was 99.1 nmol/l (pool of 24 samples) and 15.3 nmol/l in CSF (pool of 12 samples). Measurement of 5-[2H]DOPA and 5-[2H]OMD in plasma of a healthy individual who had been orally loaded with 3,5-[2H2]tyrosine (150 mg kg body wt) was possible for several hours after the load.

In Parkinson's disease, the concentration of homovanillic acid (HVA) was reduced in lumbar CSF from patients with idiopathic Parkinsonism (n = 54, P less than 0.05) and post-encephalitic Parkinsonism (n = 19, P less than 0.01). The reduction in the concentrations of 5-hydroxyindolylacetic acid (5-HIAA) was not significant, and there was no alteration in the levels of 4-hydroxy-3-methoxyphenylethylene glycol (MHPG). Treatment with L-dopa increased the concentration of HVA in the CSF (P less than 0.05) but had no effect on the levels of 5-HIAA and MHPG. Carbidopa given in combinations with L-dopa produced similar CSF concentrations of dopa as did L-dopa alone but caused less than half the rise in HVA. Fourteen patients who became functionally independent on treatment with L-dopa had higher 5-HIAA levels than 23 patients who showed no such improvement (P less than 0.001), suggesting that intact 5-hydroxyltryptamine neurones may be important in the therapeutic response to L-dopa. In a variety of movement disorders, the levels of HVA, 5-HIAA, and MHPG were not significantly different from age-matched controls. Treatment with tetrabenazine did not significantly alter the metabolite levels in patients in whom it produced either improvement, or side effects.

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.

In intact male rats the concentration of dopamine in hypophysial portal plasma of animals treated simultaneously with estradiol and progesterone was twice that of animals treated with the solvent vehicle. Treatment with estradiol or progesterone alone had no effect on dopamine in portal plasma. The rate of synthesis of dihydroxyphenylalanine (DOPA), the precursor of dopamine, in tuberoinfundibular dopaminergic (TID) neurites in the median eminence (ME) was 15 +/- 1.0 (mean +/- SE) pmol DOPA/ME.h in estradiol-progesterone-treated animals compared to 3.2 +/- 0.02 in vehicle-treated controls. Treatment with estradiol or progesterone alone gave a result similar to that seen in controls. In hypophysectomized animals treated with estradiol and progesterone, DOPA synthesis in the ME was greatly attenuated compared to that in intact rats. The in situ activity of tyrosine hydroxylase (TH; expressed as moles of DOPA per mol TH/h) in the ME was 178 +/- 16.5 in estradiol-progesterone-treated intact rats, but was 27 +/- 2.4, 52 +/- 4.2, and 35 +/- 2.5 in animals treated with the solvent vehicle, estradiol, and progesterone, respectively. In hypophysectomized rats the in situ activity of TH in the ME of animals treated with estradiol and progesterone was 53 +/- 8.4, which was significantly (P less than 0.01) less than that in similarly treated intact animals. The circulating PRL level in vehicle-treated animals was 35 +/- 4.6 ng/ml compared to 121 +/- 16 in estradiol-treated animals and 133 +/- 12.2 in estradiol- and progesterone-treated rats, indicating that the difference in the effects of estradiol and estradiol-progesterone on dopamine release, DOPA synthesis, and in situ TH activity was not solely due to a difference in circulating PRL levels. Maintenance for 7 days of anterior pituitary tissue as a graft in a lateral ventricle of intact rats resulted in a 2-fold increase in the synthesis of DOPA and TH activity in the ME compared to that in animals with liver implants. Results obtained in hypophysectomized animals with implants were similar to those in intact animals. The concentrations of PRL in cerebrospinal fluid of intact rats and hypophysectomized rats with anterior pituitary implants in the lateral ventricles were 96 +/- 32 and 127 +/- 35 ng/ml, respectively, which was significantly (P less than 0.001) greater than those in animals with liver implants. We suggest that a factor of pituitary origin stimulates TH activity in TID neurons. This stimulation may be due to PRL, but the existence of another stimulatory substance secreted by pituitary cells cannot be excluded.

We report a reliable method for determining DOPA levels in plasma and cerebrospinal fluid. The method is based on complete conversion of DOPA to dopamine and quantification by HPLC-ECD of the dopamine formed. Lower limit of detection was 0.5 nmol/l. No differences in plasma DOPA levels were found between normal children (0-15 yr, n = 60), normal adults (n = 39) and patients with essential hypertension (n = 40) or Parkinson's disease (no DOPA therapy, n = 30). In normal individuals and in patients with essential hypertension venous plasma levels were higher than arterial levels (10.2 vs 9.3 nmol/l, p less than 0.001, V/A ratio 1.11 (SD 0.08), n = 15). Sympathetic stimuli (standing, tilting, bicycle exercise, tyramine) did not influence DOPA levels. In untreated depressed patients (n = 10) and in non-parkinsonian neurological patients (n = 12) cerebrospinal fluid levels of DOPA were 4.5 (SD 2.4) and 5.2 (SD 1.3) nmol/l respectively. A direct method for the measurement of DOPA by HPLC-ECD after deproteinization of plasma is also described and compared with the conversion method. Good agreement was found when plasma DOPA levels exceeded 0.25 mumol/l (y(conversion method) = 0.943x (direct method) + 0.118; n = 60; r = 0.985). The direct method, because of greater simplicity and the possibility of simultaneous measurement of the DOPA metabolite 3-O-methyldopa, is the method of choice with plasma samples from DOPA-treated patients. In non-DOPA treated individuals the conversion method is superior and has proved to be an accurate and sensitive method for the determination of DOPA levels in plasma and cerebrospinal fluid.