Upregulation of Heat-Shock Protein (hsp)-27 in a Patient with Heterozygous SPG11 c.1951C>T and SYNJ1 c.2614G>T Mutations Causing Clinical Spastic Paraplegia

We report a 49-year-old patient suffering from spastic paraplegia with a novel heterozygous mutation and analyzed the levels of heat shock proteins (hsp)-27, dopamine (DA), and its metabolites in their cerebrospinal fluid (CSF). The hsp27 protein concentration in the patient's CSF was assayed by an ELISA kit, while DA levels and its metabolites in the CSF, 3,4-dihydroxyphenylacetic acid (DOPAC), Cys-DA, and Cys-DOPA were measured by HPLC. Whole exome sequencing demonstrated SPG-11 c.1951C>T and novel SYNJ1 c.2614G>T mutations, both heterozygous recessive. The patient's DA and DOPAC levels in their CSF were significantly decreased (53.0 ± 6.92 and 473.3 ± 72.19, p < 0.05, respectively) while no differences were found in their Cys-DA. Nonetheless, Cys-DA/DOPAC ratio (0.213 ± 0.024, p < 0.05) and hsp27 levels (1073.0 ± 136.4, p < 0.05) were significantly higher. To the best of our knowledge, the c.2614G>T SYNJ1 mutation has not been previously reported. Our patient does not produce fully functional spatacsin and synaptojanin-1 proteins. In this line, our results showed decreased DA and DOPAC levels in the patient's CSF, indicating loss of DAergic neurons. Many factors have been described as being responsible for the increased cys-DA/DOPAC ratio, such as MAO inhibition and decreased antioxidant activity in DAergic neurons which would increase catecholquinones and consequently cysteinyl-catechols. In conclusion, haploinsufficiency of spatacsin and synaptojanin-1 proteins might be the underlying cause of neurodegeneration produced by protein trafficking defects, DA vesicle trafficking/recycling processes, autophagy dysfunction, and cell death leading to hsp27 upregulation as a cellular mechanism of protection and/or to balance impaired protein trafficking.

Pharmacokinetics and pharmacodynamics of a single dose Nilotinib in individuals with Parkinson's disease

Nilotinib is a broad-based tyrosine kinase inhibitor with the highest affinity to inhibit Abelson (c-Abl) and discoidin domain receptors (DDR1/2). Preclinical evidence indicates that Nilotinib reduces the level of brain alpha-synuclein and attenuates inflammation in models of Parkinson's disease (PD). We previously showed that Nilotinib penetrates the blood-brain barrier (BBB) and potentially improves clinical outcomes in individuals with PD and dementia with Lewy bodies (DLB). We performed a physiologically based population pharmacokinetic/pharmacodynamic (popPK/PD) study to determine the effects of Nilotinib in a cohort of 75 PD participants. Participants were randomized (1:1:1:1:1) into five groups (n = 15) and received open-label random single dose (RSD) 150:200:300:400 mg Nilotinib vs placebo. Plasma and cerebrospinal fluid (CSF) were collected at 1, 2, 3, and 4 hours after Nilotinib administration. The results show that Nilotinib enters the brain in a dose-independent manner and 200 mg Nilotinib increases the level of 3,4-Dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), suggesting alteration to dopamine metabolism. Nilotinib significantly reduces plasma total alpha-synuclein and appears to reduce CSF oligomeric: total alpha-synuclein ratio. Furthermore, Nilotinib significantly increases the CSF level of triggering receptors on myeloid cells (TREM)-2, suggesting an anti-inflammatory effect. Taken together, 200 mg Nilotinib appears to be an optimal single dose that concurrently reduces inflammation and engages surrogate disease biomarkers, including dopamine metabolism and alpha-synuclein.

Biomarkers to detect central dopamine deficiency and distinguish Parkinson disease from multiple system atrophy

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.

Sex and genetic associations with cerebrospinal fluid dopamine and metabolite production after severe traumatic brain injury

Object

Dopamine (DA) pathways have been implicated in cognitive deficits after traumatic brain injury (TBI). Both sex and the dopamine transporter (DAT) 3′ variable number of tandem repeat polymorphism have been associated with differences in DAT protein density, and DAT protein affects both presynaptic DA release, through reverse transport, and DA reuptake. Catecholamines and associated metabolites are subject to autooxidation, resulting in the formation of reactive oxygen species that may contribute to subsequent oxidative injury. The purpose of this study was to determine associations between factors that affect DAT expression and cerebrospinal fluid (CSF) DA and metabolite levels after severe TBI.

Methods

Sixty-three patients with severe TBI (Glasgow Coma Scale score ≤ 8) were evaluated. The patients' genotypes were obtained using previously banked samples of CSF, and serial CSF samples (416 samples) were used to evaluate DA and metabolite levels. High-performance liquid chromatography was used to determine CSF levels of DA, 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA) during the first 5 days after injury.

Mixed-effects multivariate regression modeling revealed that patients with the DAT 10/10 genotype had higher CSF DA levels than patients with either the DAT 9/9 or DAT 9/10 genotypes (p = 0.009). Females with the DAT 10/10 genotype had higher CSF DA levels than females with the DAT 9/9 or DAT 9/10 genotypes, and sex was associated with higher DOPAC levels (p = 0.004). Inotrope administration also contributed to higher DA levels (p = 0.002).

Conclusions

In addition to systemic administration of DA, inherent factors such as sex and DAT genotype affect post-TBI CSF DA and DA metabolite levels, a phenomenon that may modulate susceptibility to DA-mediated oxidative injury.

A study of CSF catecholamine and its metabolites in acute and convalescent period of encephalitis

AIMS

To evaluate cerebrospinal fluid (CSF) catecholamine (CA) and its metabolites in encephalitis patients in acute and convalescent period and correlate these with clinical and magnetic resonance imaging (MRI) features.

SUBJECTS AND METHODS

Patients with acute encephalitis diagnosed on the basis of clinical, CSF, MRI and virological parameters underwent detailed neurological evaluation including Glasgow Coma Scale (GCS), Unified Parkinson's Disease Rating Scale (UPDRS) and Dystonia Rating Scale. Cranial MRI was carried out and CSF dopamine (DA), norepinephrine (NE), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxytryptamine (5HT) levels were estimated by High Performance Liquid Chromatography (HPLC). The CSF catecholamine levels were compared with convalescent phase as well as with controls. These levels were also correlated with parkinsonian features, dystonia and radiological abnormalities.

RESULTS

There were 29 encephalitis patients; whose age ranged between 2 and 65 years, 4 were females and 11 children. 25 patients had Japanese encephalitis (JE) and 4 nonspecific encephalitis. The mean GCS score was 8 and 13 had seizures. Movement disorders were present in 13 patients and included parkinsonian features in 5, dystonia in 1 and combination of both in 7 patients. MRI revealed abnormalities in 15 out of 21 patients and included thalamic lesion in 10, globus pallidus in 4, putamen in 5, caudate in 4 and midbrain in 9 patients. In acute stage NE, DOPAC, 5HT and HVA levels were significantly lower compared to controls. NE levels significantly correlated with dystonia and thalamic lesions. Convalescent CSF study revealed significantly lower levels of DOPAC compared to acute phase. CSF catecholamine levels in encephalitis patients with and without movement disorders were not significantly different.

CONCLUSION

In encephalitis, catecholamine and its metabolites are lower in acute and convalescent phase. Norepinephrine level correlates with dystonia and thalamic lesions.

Cerebrospinal fluid 3,4-dihydroxyphenylacetic acid level after tolcapone administration as an indicator of nigrostriatal degeneration

The development of reliable biological markers of nigrostriatal degeneration has important implications from both experimental and clinical viewpoints, since such biomarkers could be used for diagnostic and monitoring purposes in models of parkinsonism as well as in Parkinson's disease patients. In this study, levels of the dopamine metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) were measured in the cerebrospinal fluid (CSF) of normal and parkinsonian squirrel monkeys in order to assess their reliability as indicators of nigrostriatal injury. In particular, we tested the hypothesis that these measurements may become more accurate by inhibiting catecholamine-O-methyltransferase (COMT) activity and therefore blocking the conversion of DOPAC to homovanillic acid. Oral administration of the COMT inhibitor tolcapone (2 doses of 15 mg/kg each with a 4-h interval) significantly reduced enzyme activity in the monkey brain. Tolcapone treatment enhanced CSF DOPAC concentrations in unlesioned animals (by approximately four times) as well as monkeys rendered parkinsonian after severe nigrostriatal dopaminergic injury caused by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Importantly, however, COMT inhibition greatly magnified the differences in CSF DOPAC levels between control and parkinsonian monkeys, since MPTP-induced DOPAC depletion was 35% in the absence vs >60% in the presence of tolcapone. Thus, tolcapone administration enhances the detection of DOPAC in the CSF and, by doing so, improves the reliability of CSF DOPAC as a marker of nigrostriatal degeneration.

Cerebrospinal fluid monoamine and metabolite concentrations and aggression in rats

In humans and other primates low cerebrospinal fluid (CSF) levels of the major serotonin (5-HT) metabolite 5-hydroxyindoleacetic acid (5-HIAA) have been correlated to high aggressiveness. This finding forms the basis of the 5-HT deficiency hypothesis of aggression. Surprisingly, this correlation has not been confirmed in rodents so far, while manipulation studies aimed to investigate the link between 5-HT and aggressive behaviour are mostly carried out in rodents. In this study the relation between aggression and CSF monoamine and metabolite concentrations was investigated in male Wildtype Groningen rats. In sharp contrast to the hypothesis and our expectation, a clear positive correlation was found between the individual level of trait-like aggressiveness and CSF concentrations of 5-HT, 5-HIAA, norepinephrine (NE), dopamine (DA), and 3,4-dihydroxyphenylacetic acid (DOPAC). Shortly after the acute display of aggressive behaviour (as a state-like phenomenon), decreased 5-HT levels and an increase in 5-HIAA/5-HT ratio and NE concentrations were found. Surprisingly, pharmacological challenges known to influence 5-HT transmission and aggressive behaviour did not affect CSF 5-HT and 5-HIAA concentrations, only the NE level was increased. Lesioning 5-HT terminals by 5,7-dihydroxytryptamine (5,7-DHT) administration caused a decrease in CSF 5-HT and 5-HIAA, but without affecting aggressive behaviour. The observed positive correlation between CSF 5-HIAA and trait aggressiveness makes it questionable whether a direct extrapolation of neurobiological mechanisms of aggression between species is justified. Interpretation of CSF metabolite levels in terms of activity of neural substrates requires a far more detailed knowledge of the dynamics and kinetics of a neurotransmitter after its release.

Monoamine compounds in cerebrospinal fluid of healthy subjects punctured without preceding strict bed rest: a pilot study

The interpretation of data on compounds in the lumbar cerebrospinal fluid (CSF) is limited by several confounding factors, e.g. motor activity for which strict bed rest prior to lumbar puncture is recommended for standardisation. Now we report data from 14 healthy males employing the standardised procedure except for the requirement of strict bed rest. The levels of serotonin, noradrenaline, 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid and 4-hydroxy-3-methoxyphenylglycol in the second CSF fraction (7-12 ml) were significantly higher than those in the first fraction (0-6 ml), indicating the presence of concentration gradients. 5-HIAA was negatively influenced by age and the neuraxis distance in the lying position and positively by atmospheric pressure. Storage time and atmospheric pressure contributed to the variance in dopamine. Both tyrosine, tryptophan and dopamine were linearly correlated with storage time. We also found a significant curvilinear correlation between tapping time and atmospheric pressure. On comparing with previous studies, the results support the notion that the issue of strict bed rest or not prior to lumbar puncture might have to be taken into consideration when interpreting lumbar monoamine CSF data.

Behavioral evaluation of hemiparkinsonian MPTP monkeys following dopamine pharmacological manipulation and adrenal co-graft transplantation

Bradykinesia and rigidity are the symptoms that most directly correlate with loss of striatal dopamine in Parkinson's disease. In the hemiparkinsonian (HP) monkey, this is represented by paucity of movement as measured by coli puterized movement analysis, diminished manual dexterity on clinical examination, and diminished performance on operant behavioral tasks. The present study used an MPTP-induced HP model in rhesus monkeys to evaluate the effectiveness of adrenal medullary and peripheral nerve co-grafts in diminishing parkinsonian symptoms. Unoperated controls (N = 4), surgical controls with caudate lesioning (N = 4), and caudate co-grafted (N = 4) HP monkeys demonstrated diminished movement in the home cage following MPTP. This behavior persisted in unoperated controls, but improved in both surgical control and co-grafted monkeys. Functional hand dexterity evaluations demonstrated similar impairment in all three groups but only surgical controls and co-grafted monkeys demonstrated improvement. In general, rotational behavior in response to apomorphine was consistent with recovery of function in surgical controls and co grafted monkeys, but marked between-subject variability precluded group statistical analyses. None of the monkeys could perform the operant task using the affected limb following MPTP. However, the performance of two co-grafted animals demonstrated partial recovery. L-dopa improved operant performance, demonstrating a dopaminergic component to the task. The results demonstrate recovery of behavioral function after surgical treatment, with adrenal co-grafted monkeys showing the greatest degree of improvement.

Changes in monoamine metabolites concentrations in rat cerebrospinal fluid after acute and long-term administration of a selective serotonin reuptake inhibitor, trazodone

In order to clarify the mechanism of the antidepressive effects of trazodone, a selective serotonin reuptake inhibitor, we investigated the dynamics of monoamine metabolites in cerebrospinal fluid (CSF) of free-moving conscious rats by acute and long-term treatment with trazodone. When 100 mg kg-1 p.o. of trazodone were administered, a significant increase of 3-methoxy-4-hydroxyphenylglycol (MHPG) concentration was soon observed in the light period of the light/dark cycle, and a significant decrease of dihydroxy phenyl acetic acid (DOPAC) concentration was observed during the 2 days after administration of trazodone; in contrast, the homovanilic acid (HVA) level was increased. However, we detected no significant changes in the 5-hydroxy indole-3-acetic acid (5-HIAA) concentration during the 3 days. In the case of long-term treatment with 50 mg kg-1, p.o. of trazodone, the levels of MHPG, DOPAC and HVA exhibited no difference when compared with values obtained during saline treatment in either the light or dark period, whereas the levels of 5-HIAA showed a significant increase during the light period. These findings suggest that a long-term treatment with trazodone enhances the serotonergic neurons.

Biogenic amine activity in response to fluoxetine and desipramine in differentially reared rhesus monkeys

BACKGROUND

It has been hypothesized that adverse early experience may be a mechanism by which children become vulnerable to later psychopathology via alteration of neurochemical or hormonal systems associated with such disorders. Such effects may in turn affect later responses to pharmacologic agents that act on these systems.

METHODS

In this study, 18 mother-reared (MR) and 18 peer-reared (PR) rhesus monkeys experienced six 1-week separations from cagemates interspersed with 1-week reunions, while housed in like-reared groups of 3. Within rearing groups, equal numbers of animals received either fluoxetine (2 mg/kg), desipramine (5 mg/kg) or placebo delivered daily beginning 4 weeks before the first separation. Levels of norepinephrine (NE), the NE metabolite MHPG, the dopamine metabolites DOPAC and HVA, and the serotonin metabolite 5HIAA were measured in CSF samples collected approximately every 2 to 3 weeks during these procedures.

RESULTS

Following treatment, DMI increased NE and decreased MHPG in the DMI-treated groups, while 5HIAA was decreased in the fluoxetine-treated groups following treatment. The increase in NE was followed by a sharp decline over the course of treatment, which was accompanied by an increase in MHPG. The rearing groups did not show a differential response to the drug treatments, and the separation manipulation itself had few effects. The mother-reared group showed higher levels of NE and DOPAC over all samples and higher levels of HVA in most samples.

CONCLUSIONS

These rearing effects on biogenic amine activity were observed even in the presence of pharmacologic treatments that effectively altered the activity of these systems, and are consistent with previous findings from the same subject. The higher NE values observed in mother-reared infants over separations and reunions may have been due to higher basal levels of NE than peer-reared monkeys or to greater responsiveness to the stress of repeated social disruption or both. These findings agree with other primate studies showing that rearing differences persist beyond the infancy period and add to growing evidence of the important influence of the early social environment on neurobiologic development in primates.

Alteration of dopamine metabolites in CSF and behavioral impairments induced by neonatal hippocampal lesions

Alterations of monoamine metabolites in CSF and behavioral abnormalities were studied in rats with neonatal hippocampal lesions and controls. Lesions of the ventral hippocampus were produced bilaterally by ibotenic acid on postnatal day 7. Lesion-induced neurochemical alterations and behavioral impairments were examined concurrently when rats were 12 weeks old. CSF from the cisterna magna was sampled repeatedly from freely moving rats. The levels of free 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) in CSF were determined. An exposure to a novel environment induced hyperexploratory behavior and elevated the level of free DOPAC in CSF in lesioned rats. Although a swim stress increased the levels of free DOPAC and 5-HIAA in CSF in both control and lesioned groups, rats with hippocampal lesions had a further elevation of free DOPAC in CSF and greater spontaneous activity relative to controls shortly after stress. Amphetamine (1.5 mg/kg, i.p.) induced hyperlocomotion in lesioned rats compared to controls. For the control group, the levels of the three monoamine metabolites in CSF were not significantly influenced by amphetamine. However, for the lesioned group, the level of DOPAC significantly decreased compared to preinjection of amphetamine. The results indicate that neonatal hippocampal lesion-induced impairments can be manifested by behavioral and neurochemical abnormalities. Alterations of monoamine metabolites in CSF may be determined quantitatively and used as indices for monitoring lesion-impaired monoaminergic function in the central nervous system.

Chronic exposure to MPTP as a primate model of progressive parkinsonism: a pilot study with a free radical scavenger

The development of a validated primate model of progressive parkinsonism is a critical step in the evaluation of drugs that might halt or slow progression of Parkinson's disease. In this pilot study, we gradually exposed 14 cynomolgus monkeys to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), at a weekly dose of 0.5 mg/kg s.c. for 10 weeks, to determine their probability of not reaching a predetermined endpoint on a disability scale by Kaplan-Meier analysis. Four other MPTP-exposed animals were coadministered the potent free radical scavenger 7-hydroxy-1-[4-(3-methoxyphenyl)-1-piperazinyl]acetylamino-2,2,4,6- tetramethylindan (OPC-14117) as a single oral daily dose of 0.6 g/kg, starting 2 weeks before MPTP initiation. The risk of reaching endpoint by week 10 was 79% and mean time before reaching endpoint was 6 weeks. Global motor activity, recorded in a subset of animals using a portable activity monitor, declined following the first MPTP dose and never recovered. Several cerebrospinal fluid indices of central monoamine metabolism collected by suboccipital puncture at 0, 5, and 10 weeks, including HVA, DOPAC, and tetrahydrobiopterin but not MHPG, were found to be "trait" markers for MPTP exposure, whereas CSF DOPAC and tetrahydrobiopterin constituted potential "state" markers for reaching endpoint. The antioxidant OPC-14117 did not protect against MPTP-induced parkinsonism. Further attempts to validate this incremental model of neurotoxin-induced parkinsonism as a predictor of patient responses to putative neuroprotective agents appear warranted.

Variation of monoamines and their metabolite contents in the cerebrospinal fluid of conscious rats

To study the circadian rhythm of the monoamine and metabolite contents, cerebrospinal fluid was taken from the cisterna magna through a polyethylene catheter tube every 4 hr in the conscious rat. Norepinephrine and 3-methoxy-4-hydroxy-phenylglycol were found to describe a rhythm with the maximal content occurring during the dark phase and the minimal content occurring during the light phase. Dopamine levels increased significantly during the light phase compared with the dark phase. These results, given that cerebrospinal fluid can be taken chronically from conscious rats, indicate that our present method may be suitable for estimating changes in brain monoamine and metabolite contents.

Monoaminergic effects of high-dose corticotropin in corticotropin-responsive pediatric opsoclonus-myoclonus

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.

Monoamine metabolite levels in CSF of SIV-infected rhesus monkeys (Macaca mulatta)

Increasing evidence suggests the involvement of the basal ganglia in HIV-1-infected patients. We used SIV-macaques, an animal model of HIV-1 infection, to investigate changes in CSF biogenic amine metabolites over time and compared them with control animals. The dopamine and serotonin metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA), were analysed by reverse-phase chromatography with electrochemical detection. DOPAC concentrations were significantly increased in SIV-infected animals compared with controls. 5-HIAA and HVA remained unchanged. However, the longitudinal assessment of metabolites up to 3 months post-infection revealed a significant increase in 5-HIAA. Our results reflect the effects of SIV early stage infection on monoamine systems in brain and further validate the simian model for AIDS research.

Altered dopamine function in pathological gambling

BACKGROUND

The possibility that monoaminergic neurotransmission is altered in pathological gambling was examined.

METHODS

Monoamines and their metabolites were measured in CSF obtained at level L4-5 from ten pathological gamblers and seven controls.

RESULTS

A decrease in dopamine and an increase in 3,4-dihydroxyphenylacetic acid and homovanilic acid was found. Noradrenaline and its metabolite 3-methoxy-4-hydroxyphenylglycol was also increased but 5-hydroxytryptamine and 5-hydroxyindoleacetic acid were unchanged.

CONCLUSION

It is suggested that the function of the dopaminergic system, possibly mediating positive and negative reward, and the noradrenergic system, possibly mediating selective attention, is changed in pathological gambling.

The relationship between urine excretion and biogenic amines and their metabolites in cerebrospinal fluid of schizophrenic patients

Concentrations of norepinephrine and metabolites of biogenic amines were measured in lumbar cerebrospinal fluid of 30 patients with chronic schizophrenia, nine of whom were polyuric. The mean level of norepinephrine was two-fold higher (p < or = 0.025) in polyuric patients than in patients whose excretion of urine was within the normal range. CSF levels of histamine's primary metabolite, tele-methylhistamine, an index of brain histaminergic activity, were positively correlated (p < 0.005) with daily urine volume. These results are consistent with the known influence of norepinephrine and histamine on fluid regulation and suggest that norepinephrine and histamine may be involved in psychogenic polydipsia-polyuria in schizophrenic patients.

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

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

Cerebrospinal fluid tyrosine and 3,4-dihydroxyphenylacetic acid levels in migraine patients

We studied biochemical parameters related with central dopaminergic neurotransmission in migraine patients during crisis. We determined tyrosine and 3,4-dihydroxyphenylacetic acid (DOPAC) levels in cerebrospinal fluid (CSF) of 47 patients, 29 suffering migraine without aura and 18 suffering migraine with aura, comparing them with 27 control subjects. Tyrosine levels did not differ significantly between patients and controls. The CSF concentration of DOPAC was 0.73 +/- 0.55 ng/ml in the control population, 3.84 +/- 2.08 ng/ml in patients with migraine without aura and 3.30 +/- 1.49 ng/ml in patients suffering migraine with aura. The concentration of DOPAC correlated positively with the intensity of headache. These results suggest that patients with migraine have a central dopaminergic hyperfunction, probably related to a coexisting central dysfunction of noradrenergic neurotransmission.

Slow increase of homovanillic acid in cerebrospinal fluid after levodopa administration

Concentrations of major catabolites of dopamine were followed in the ventricular cerebrospinal fluid (CSF) in five patients undergoing intracranial pressure monitoring for chronic hydrocephalus. Determinations were made every 2 h following the administration of carbidopa/levodopa 25/250 mg (one Sinemet capsule) given 8 h apart. The rise of homovanillic acid (HVA) concentrations was slow and progressive, reaching the level of statistical significance (p < or = 0.01) only 8 h after the second administration of Sinemet. The rise in 3,4-dihydroxyphenylacetic acid (DOPAC) was faster than the rise in HVA, with the peak value detected 4 h after the first administration of Sinemet. These data are interpreted as a confirmation, in humans, of a slow pool of exogenous levodopa, previously demonstrated in animal studies.

CSF and plasma concentrations of free norepinephrine, dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), 3,4-dihydroxyphenylalanine (DOPA), and epinephrine in Parkinson's disease

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.

Effects of the catechol-O-methyltransferase inhibitor tolcapone in Parkinson's disease: correlations between concentrations of dopaminergic substances in the plasma and cerebrospinal fluid and clinical improvement

We compared the concentrations of dopaminergic substances in the plasma and cerebrospinal fluid (CSF) with clinical severity in patients with Parkinson's disease (PD) under L-dopa/carbidopa treatment and under L-dopa/carbidopa+tolcapone treatment. Compared with treatment with L-dopa/carbidopa alone, the co-administration of tolcapone produced a significant decrease in clinical severity; a remarkable reduction in the 3-O-methyldopa (3-OMD) concentration and significant increase in the L-dopa concentration both in the plasma and CSF; and a significant increase in the dopamine concentration in the CSF. The clinical effects of tolcapone were closely correlated with the reduction in the 3-OMD concentration, but not with the increase in the dopamine and L-dopa concentrations in the CSF.

Markers of dopamine depletion and compensatory response in striatum and cerebrospinal fluid

Though depletion of CSF homovanillic acid (HVA) concentration has often been regarded as a direct indicator of dopamine (DA) deficiency in Parkinson's Disease (PD), CSF HVA is normal in mildly affected patients. To explore why, we measured DA and its metabolites in striatum and CSF in rabbits receiving reserpine for 5 days. Reserpine, which depletes striatal DA by disrupting vesicular storage of the neurotransmitter, results in a compensatory increase of DA turnover. In response to a 96% depletion of striatal DA, its catabolic intermediates 3,4-dihydroxyphenylacetic acid (DOPAC) and 3-methoxytyramine (3-MT) decreased 64% and 92% in striatum, although the endproduct, HVA, was unchanged. In contrast, CSF concentrations of HVA and DOPAC increased significantly, though 3-MT and levodopa (LD) were unaltered. A 5-fold rise in striatal LD concentration after reserpine-induced DA depletion provided evidence for enhanced DA synthesis. As in PD, the compensatory increase of DA synthesis after reserpine administration confounds the ability of CSF HVA to reflect DA depletion.

Cerebrospinal dopamine metabolites in rats after intrastriatal administration of 6-hydroxydopamine or 1-methyl-4-phenylpyridinium ion

Dopamine (DA) and its main cerebral metabolites, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were measured in striatum and cerebrospinal fluid (CSF) from cisterna magna in rats bilaterally lesioned by intrastriatal administration of 6-hydroxydopamine (6-OHDA) or 1-methyl-4-phenylpyridinium ion (MPP+). 6-OHDA caused a progressive lesion in striatum that is only moderately reflected in the decrease in dopamine metabolite concentration in CSF. MPP+ caused an acute but less selective lesion in the dopamine striatal system, as indicated by a significant reduction in striatal GABA content, followed by a slow recovery in dopamine striatal metabolism and content. The locomotor activity was dramatically reduced in both groups 48 hours after the treatment but remained significantly decreased after two months only in 6-OHDA lesioned animals. A positive correlation was found between HVA CSF concentration and striatal DA content in MPP+ lesioned rats, but not in 6-OHDA lesioned rats. It is concluded that the concentration of dopamine metabolites in CSF can be altered only after a severe striatal lesion: reduction of striatal dopamine content below 50% of normal values and involvement of neuronal or non-neuronal elements other than the dopaminergic system, similarly to the lesions caused by MPP+. These results may partly explain why CSF dopamine metabolites concentrations were significantly decreased both in advanced stages of parkinsonism and in other neurodegenerative disorders.

Peripheral and central pharmacokinetics of apomorphine and its effect on dopamine metabolism in humans

Apomorphine is a dopamine receptor agonist increasingly used in the treatment of Parkinson's disease (PD). In the present study, we examined the plasma and ventricular cerebrospinal fluid (CSF) pharmacokinetics of apomorphine as well as its effects on dopamine metabolism in six patients (one woman and five men, mean age 79.5 years) without evidence of PD who underwent 48-h intracranial pressure monitoring for suspected normal pressure hydrocephalus. Maximal plasma apomorphine concentration (25.04 ng/ml) is found 20 min after subcutaneous injection (50 micrograms/kg), and the mean area under the curve is 1,439.37 ng/ml for 120 min. In contrast to plasma values, the maximal ventricular CSF apomorphine concentration (1.08 ng/ml) is found 30 min after injection and the mean area under that curve is 7% of that of plasma (96.69 ng/ml for 120 min). Apomorphine administration causes a significant reduction in ventricular CSF concentrations of dopamine and of its major metabolites sulfoconjugated dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), and homovanillic acid (HVA). This effect starts 10 min after the injection of apomorphine, is maximal after 30 min (free dopamine, -30%; sulfoconjugated dopamine, -28%; HVA, -21%; DOPAC, -31%) and is still present, although to a lesser extent (-5 to -10%), 120 min after the injection of apomorphine. This study shows that in humans a dose of apomorphine commonly used in PD causes significant inhibition of dopamine metabolism lasting > 120 min. In addition to their symptomatic effects, dopamine agonists such as apomorphine may play a role in preventing or slowing the neurodegeneration in PD by autoreceptor-mediated inhibition of dopamine metabolism.

Monoamine concentrations in cerebrospinal fluid of fetal and newborn sheep

Monoamine concentrations were measured in cisternal cerebrospinal fluid (CSF) of unanesthetized fetal (115-135 days gestation) and newborn (2-34 days old) sheep. Norepinephrine (NE) and 3,4-dihydroxyphenylacetic acid (DOPAC) concentrations decreased with gestational age; NE CSF concentrations were significantly higher in the newborn (336.4 +/- 61.7 pg/ml; n = 5) compared with the 131- to 135-day-gestation fetuses (104.0 +/- 46.3 pg/ml, n = 3; P < 0.05). Dopamine (DO), homovanillic acid (HVA), and serotonin (5-HT) concentrations in fetal CSF did not change with gestational age, and epinephrine (Epi) was undetectable in most fetal and newborn samples. Hypoxia, induced by giving the ewe 9% O2 in N2 to breathe for 30 min, resulted in a 10.78 +/- 3.94-fold (n = 5) increase of NE concentration in fetal CSF (P < 0.05); DO and DOPAC concentrations did not change. Hypoxia did not increase NE concentrations in CSF of newborn lambs. Inhibition of prostaglandin (PG) synthesis by intravenous infusion of indomethacin significantly reduced plasma prostaglandin E2 concentrations from 7.8 +/- 1.0 (n = 6) to 2.5 +/- 0.2 nmol/l (n = 3; P < 0.05), and was associated with an increase of CSF DOPAC concentrations from 2,156.3 +/- 504.5 (n = 9) to 5,453.6 +/- 1,091.3 pg/ml (n = 5; P < 0.05); NE and DO concentrations did not change significantly. These results show that catecholamines and indoleamines are released in the brain and enter the CSF of fetal sheep from at least 115 days gestation. The data also show that concentrations of some monoamines in CSF are changed by fetal hypoxia or prostaglandin synthesis.

Neurochemical profiles in cerebrospinal fluid of stroke-prone spontaneously hypertensive rats

The purpose of the present study was to evaluate stroke-prone spontaneously hypertensive rats (SHRSP) neurochemically by determining the cerebrospinal fluid (CSF) levels of acetylcholine (ACh), norepinephrine (NE) and serotonin (5-HT) as an index of central neuronal activity. The CSF ACh levels of 15- to 20-week-old SHRSP were significantly lower than those of age-matched Wistar Kyoto rats (WKY) both under the urethane/alpha-chloralose anesthesia and in freely moving conditions. The difference in the CSF ACh levels between SHRSP and WKY was more marked at 30-40 weeks. Sustained changes were not observed in the CSF NE and 5-HT levels. Thus, the progressive dysfunction in the central cholinergic system may characterize the pathophysiological state of this animal model with cerebral lesions caused by continuous high blood pressure.

Chlorpromazine attenuated electroacupuncture analgesia in conscious rabbits

By measuring the defense behavior in response to the noxious stimulation induced by potassium iontophoresis on ear-lobe skin of conscious rabbit, chlorpromazine (CPZ) (0.5 mg.kg-1, i.v.) induced hyperalgesia, whereas it significantly attenuated electroacupuncture analgesia (EAA) efficacy. Monoamines and their metabolites in cerebrospinal fluid (CSF) were measured by high pressure liquid chromatography with electrochemical detector (HPLC-ECD) while the attenuation effect of CPZ on EAA was observed. CPZ markedly enhanced 3,4-dihydroxyphenylacetic acid (DOPAC) (P < 0.05) and homovanillic acid (HVA) (P < 0.01) contents in CSF both in the presence and absence of electroacupuncture. CPZ attenuated EAA with elevations of either DOPAC or HVA concentrations in CSF. There was a positive correlation between the increase of DOPAC or HVA content in CSF and the attenuation effect of CPZ on EAA (P < 0.05). These results suggested that the activation of dopamine system was unfavorable for EAA.

Milacemide effects on the temporal inter-relationship of amino acids and monoamine metabolites in rat cerebrospinal fluid

The temporal inter-relationship of various amino acids and monoamine metabolites in rat cerebrospinal fluid was examined after acute administration of milacemide (100, 200 or 400 mg/kg i.p.), a glycine prodrug. Glycine concentrations rose linearly and dose dependently (20-190%) but were only significantly elevated at the higher milacemide dose (200 and 400 mg/kg). In animals given 400 mg/kg, glycine values were still significantly elevated 8 h later. A concomitant increase (20-25%) in serine and taurine and a decrease in alanine cerebrospinal fluid values were observed at the highest milacemide dose. Other amino acids were unaffected. While cerebrospinal fluid 5-hydroxyindoleacetic acid concentrations were unaffected, the dopamine metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid, exhibited a linear dose-dependent reduction. However, only homovanillic acid values were significantly decreased after 400 mg/kg milacemide. Cerebrospinal fluid analysis may be useful as a first screen in ascertaining putative neurochemical changes associated with drug administration.

Monoamine metabolites in normal human cerebrospinal fluid and in degenerative diseases of the central nervous system

Measurement of monoamine metabolites in cerebrospinal fluid (CSF) has been one of the few methods available to study monoamine transmitter function in the human central nervous system (CNS). It has steadily proved to be of much use in clinical research of neurological and psychiatric diseases, in which altered functions of central monoamine neurotransmitters have been identified. In this work 3-methoxy-4-hydroxyphenylethylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA) were quantified in normal CSF and in patients with untreated Parkinson's disease (PD) and olivopontocerebellar atrophy (OPCA). Normal CSF was obtained from 162 patients at the time of spinal anesthesia for surgery. Reference values for monoamine metabolites were established for normal adult lumbar CSF. Up to the age of 70 years no relation of monoamine metabolite concentration with age or sex were encountered. In individuals above 70 years of age higher levels of MHPG, HVA, and 5-HIAA were present in women, while in men only higher levels of MHPG could be detected. A strong correlation between 5-HIAA and HVA concentrations were observed in all groups. PD patients exhibited normal CSF metabolite levels, but an altered 5-HIAA/HVA ratio, favoring 5-HIAA. Dominant and recessive OPCA differed essentially in HVA concentration-diminished in the first group and elevated in the last. Comparing the results obtained in PD and dominant OPCA, we suggest that the decrease of CSF HVA in the latter group might not reflect nigrostriatal degeneration as we previously thought. Possibly another factor influencing dopamine function in the CNS is involved.

Effects of beta-carboline on fear-related behavioral and neurohormonal responses in infant rhesus monkeys

We examined the effects of the inverse benzodiazepine agonist ethyl-beta-carboline-3-carboxylate (beta-CCE) on behavioral, hormonal, and neurochemical responses in infant rhesus monkeys exposed to fearful situations. Our paradigm elicits three distinct adaptive patterns of defensive behavior. From previous work, we hypothesized that behaviors induced by attachment bond disruption are predominantly mediated by opiate systems, whereas behaviors induced by the threat of attack are mediated by benzodiazepine systems. When beta-CCE (0, 125, 250, and 500 micrograms/kg) was administered immediately after maternal separation, the 500 micrograms/kg dose increased freezing and the 250 and 500 micrograms/kg doses reduced environmental exploration. Test conditions produced increased plasma ACTH and cortisol concentrations and increased cerebrospinal fluid (CSF) concentrations of MHPG and DOPAC; beta-CCE did not further affect these metabolites. A dose of 1000 micrograms/kg of beta-CCE increased CSF concentrations of DOPAC and MHPG in infants left with their mothers. During test conditions, it further increased CSF MHPG (but not DOPAC) concentrations, and reduced cooing while increasing freezing and barking and other hostile behaviors. Our results thus confirm that benzodiazepine systems mediate threat-related behaviors and suggest that coos, which were thought to predominantly reflect the degree of distress during separation, can be modulated by the infant's level of fear. beta-CCE also activated stress-related pituitary-adrenal hormonal systems and brain norepinephrine (NE) and dopamine (DA) systems. These effects occurred when animals remained undisturbed in their home cages with their mothers, suggesting that benzodiazepine receptors directly modulate brain NE and DA systems.

Cerebrospinal fluid and serum levels of dopa, catechols, and monoamine metabolites in patients with epilepsy

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.

Tryptophan and biogenic amine metabolites in post-mortem human cisternal fluid: Effects of post-mortem interval and agonal time

Cisternal fluid (CF) tryptophan (TRP), 5-hydroxyindole-3-acetic acid (5-HIAA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) concentrations were measured from 40 adult cadavers. They were divided into 4 groups (n = 10 in each group), with samples taken 2, 4, 10 and 24 h after death. The CF concentrations of TRP and all determined biogenic amine metabolites were distinctly higher than in lumbar CSF during life, and concentrations of 5-HIAA were also higher in post-mortem samples than in cisternal or ventricular CSF in living humans. The means of the samples of 5-HIAA, DOPAC, HVA and MHPG were not statistically significantly different over time, but some trends were evident. TRP concentrations in CF increased linearly with time (from 4.6 to 23.6 mumol/l, P less than 0.001). CF DOPAC and HVA concentrations were dependent on agonal time and dopamine infusions. Our results imply that both ante-mortem and post-mortem conditions may influence monoamine metabolite and TRP concentrations in CF. These conditions should be accounted for in studies using post-mortem samples to study differences between patient groups in CNS neurochemistry.

Diazepam and atropine as premedicants: no discrimination by monoamine metabolite and catecholamine measurements in cerebrospinal fluid and plasma

The relationships between self-reported assessments of the quality of the preoperative night's sleep, preoperative anxiety, and several biochemical and physiological indicators of stress reaction were investigated in pregnant women at term receiving no premedication (n = 15), a placebo tablet (n = 15), diazepam 5 mg p.o. (n = 15), or atropine 0.01 mg/kg i.m. (n = 15), in connection with spinal analgesia for elective caesarean section. In the patients receiving no premedication, the subjective estimate of the quality of the preoperative night's sleep was negatively associated with concentrations of noradrenaline (NA) and its metabolite, 3-methoxy-4-hydroxyphenylglycol (MHPG) in CSF, and with plasma adrenaline. The anxiolytic effect of diazepam was reflected as significantly lower plasma levels of another metabolite of NA, 3,4-dihydroxyphenylglycol (DHPG). Placebo and diazepam, and to a lesser extent atropine, confounded the statistical relationships between the clinical and biochemical responses found in the patients with no premedication. On the whole, the biochemical monoamine measurements were of little use in determining the clinical effects of different kinds of premedicants.

Increased cerebrospinal fluid dopamine and 3,4-dihydroxyphenylacetic acid levels in Huntington's disease: evidence for an overactive dopaminergic brain transmission

Levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), noradrenaline (NA), 3-methoxy-4-hydroxyphenylglycol (MHPG), and 5-hydroxyindoleacetic acid (5-HIAA) in the CSF of patients with Huntington's disease (HD) were measured by HPLC. CSF DA, DOPAC, and MHPG levels were found to be increased in HD patients. Levels of HVA, 5-HIAA, and NA in the CSF of HD patients did not differ from those of controls. Changes in CSF DA and DOPAC levels were consistent with previous findings of increased DA tissue content in some brain areas of patients with HD. These results suggest that CSF DOPAC levels could be a more reliable index of overactive dopaminergic brain systems in HD than CSF HVA levels.

Analysis of monoamines in the cerebrospinal fluid of Chinese patients with Alzheimer's disease

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.

Neurochemical changes correlated with behavior maintained under fixed-interval and fixed-ratio schedules of reinforcement

Key pecking of 4 pigeons was maintained under a multiple 3-min fixed-interval, 30-response fixed-ratio schedule of food presentation. Only one schedule was in effect during an experimental session, and each was correlated with a different keylight stimulus and location (left vs. right). The different schedule components alternated across days or weeks. Cerebrospinal fluid was collected from chronically implanted intracerebroventricular cannulae following sessions with the different schedules, as well as following sessions in which reinforcement was withheld (extinction), when response-independent food was delivered, and when the experimental chamber was dark and there were no scheduled events. Metabolites of the neurotransmitters serotonin, norepinephrine, and dopamine were assayed in cerebrospinal fluid using high-performance liquid chromatography with electrochemical detection. Compared to the fixed-ratio condition, responding maintained under the fixed-interval schedule resulted in consistently higher levels of the serotonin metabolite 5-hydroxyindoleacetic acid and of the dopamine metabolite homovanillic acid in all pigeons. Levels of 3-methoxy-4-hydroxyphenylethylene glycol, a metabolite of norepinephrine, and dihydroxyphenylacetic acid, another dopamine metabolite, were also higher in 3 of the 4 pigeons following exposure to the fixed-interval schedules when compared to levels of these metabolites after exposure to the fixed-ratio schedule. Extinction of fixed-ratio responding resulted in large increases in 5-hydroxyindoleacetic acid compared to levels of this metabolite under the fixed-ratio schedule, whereas this serotonin metabolite decreased during extinction of responding under the fixed-interval schedule. Control procedures suggested that the neurochemical changes were not related to the rate of responding but were a function of the specific experimental conditions. Distinctive neurochemical changes that accompany schedule-controlled responding show the sensitivity of the neurochemical environment to behavioral contingencies and demonstrate further the profound impact that such contingencies have on biobehavioral processes.

Strangers in a strange land: a psychobiological study of infant monkeys before and after separation from real or inanimate mothers

Some rhesus monkey (Macaca mulatta) infants have a "despair" or depression-like response to mother-infant separation, while others do not. The presumed interrelation between early rearing conditions and the neurobiological status of the infant that might lead to increased risk for despair is not understood. In this study, the characteristics of the "mother" were controlled by rearing infant rhesus monkeys with their biological mothers, or with inanimate mothers. Behavioral data were collected before and after separation at 6-7 months of age. The neurobiological status of the infants was evaluated by measuring the concentration of norepinephrine, its major metabolite, and the metabolites of dopamine and serotonin in cerebrospinal fluid. The results suggest that despair is not simply a behavioral response to separation. Instead, despair may reflect the inability to cope with the separation environment. Coping with the separation environment appears to depend on neurobiological and behavioral characteristics of the infant that are related to, if not determined by, characteristics of the mother.

Biochemical assessment of preoperative stress: a study with diazepam and measurement of monoamine metabolites and catecholamines in cerebrospinal fluid and plasma

Diazepam 5 mg or an inert placebo tablet was given as preoperative hypnotic on the night before operation to two groups (n = 18 in each) of healthy women having elective Caesarean section under spinal analgesia. A third group (n = 18) received no hypnotic. The quality of the preoperative night's sleep assessed subjectively was significantly better in the diazepam-treated patients compared with those receiving no drug. The diazepam-treated patients had also smaller CSF concentrations of noradrenaline (NA) and of the dopamine metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC). In comparison with the two other patient groups, in the diazepam group there was no correlation between demographic, physiological or subjectively estimated variables and CSF or plasma measurements of monoamine transmitters and their metabolites. Preoperative fear and apprehension correlated most strongly with preoperative heart rate and with the increase in heart rate from the previous day. The monoamine neurotransmitters or their metabolites were of limited use in monitoring the intensity of preoperative fear and anxiety.

Personality and cerebrospinal fluid monoamine metabolites in alcoholics and controls

Alcoholics as a group have been consistently reported to show differences from controls on various personality inventories. Moreover, neurobiologic substrates have been postulated to underlie personality dimensions. Therefore, we compared alcoholics with controls on measures of personality and investigated relationships between measures of personality and cerebrospinal fluid monoamine metabolite concentrations. The alcoholics were significantly different from controls on many personality measurements. There were significant, negative correlations between interview-derived lifetime aggression scores and cerebrospinal fluid concentrations of both the serotonin metabolite 5-hydroxyindoleacetic acid and the dopamine metabolite homovanillic acid. However, there were no significant correlations between any cerebrospinal fluid monoamine metabolite concentrations and scores on personality inventories.

Concentrations of cerebrospinal fluid monoamine metabolites in suicides

Reanalysis of data from a Japanese report indicated that suicides had lower cerebrospinal fluid levels of 3,4-dihydroxyphenylacetic acid and 3-methoxy-4-hydroxyphenylglycol than those dying of heart failure.

Biological correlates of mental stress related to anticipated caesarean section

The relationships between self-reported assessments of acute anxiety and several biochemical and physiological indicators of stress reaction were investigated in pregnant women at term in connection with spinal analgesia for caesarean section. Fear and apprehension were statistically significantly associated only with blood pressure and with an increase in heart rate from the previous day. The subjective estimate of the quality of the preoperative night's sleep was negatively associated with biochemical plasma and cerebrospinal fluid (CSF) measures of sympatho-adrenal activity. The previously reported negative correlation between body height and 5-hydroxyindoleacetic acid (5-HIAA, an indicator of serotonin metabolism) in lumbar CSF was confirmed. The concentration of 5-HIAA in CSF was positively correlated with the levels of other acidic monoamine metabolites and cortisol in CSF. It is concluded that hormone and monoamine metabolite measurements in CSF and plasma have only limited usefulness as quantitative indicators of the intensity of preoperative fear and anxiety.

Chronic treatment with talipexole dihydrochloride on abnormal involuntary movement in humans

Two cases of severe dystonia and dyskinesia were treated with talipexole, a dopamine autoreceptor agonist, and the metabolites of dopamine, norepinephrine, and serotonin in cerebrospinal fluid (CSF) were determined. Despite significant reductions in these metabolites in CSF, behavioral amelioration of these cases could not be observed. The present findings argue for further studies to explore the clinical usefulness of dopaminergic agonists such as talipexole.

Simultaneous determination of DOPAC, MHPG, 5-HIAA and HVA in CSF by direct injection on a liquid chromatograph with coulometric detection

We describe a direct analysis for simultaneous determination of 3,4-dihydroxyphenylacetic acid (DOPAC), 3-methoxy-4-hydroxyphenylglycol (MHPG), 5-hydroxyindoleacetic acid (5-HIAA), and 4-hydroxy-3-methoxyphenylacetic acid (HVA). After ultrafiltration the samples are applied directly to a high-performance liquid chromatograph with coulometric detection. The appropriate choice of the potentials of the three-coulometric-electrode system eliminates many possible interfering substances. One chromatographic run requires less than 15 min. By this analytical system the lowest amount of DOPAC, MHPG, 5-HIAA and HVA detectable was 0.16, 0.18, 0.90, and 1.48 ng/ml respectively. Coefficient of variation was less than 5% for "within-run" precision and less than 10% for "between-run" precision.

Simultaneous high-performance liquid chromatographic determination of norepinephrine, serotonin, acetylcholine and their metabolites in the cerebrospinal fluid of anaesthetized normotensive rats

A high-performance liquid chromatographic method with electrochemical detection was developed for the simultaneous determination of the levels of norepinephrine (NE), serotonin (5-HT), acetylcholine (ACh) and their metabolites in the cerebrospinal fluid (CSF) of anaesthetized rats. The response curve for each compound was linear for the concentration way of interest. The within- and between-day coefficients of variation (C.V.) for NE, 5-HT and their metabolites were less than 7.85% and 15.67%, respectively, and those for ACh and choline were less than 3.08% and 6.27%, respectively. This simultaneous determination should be useful for elucidating the noradrenergic, serotonergic and cholinergic nerve activity in the central nervous system.

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.

Electrochemical analysis of hypothalamic serotonin metabolism accompanied by immobilization stress in rats

The effects of stress on serotonin metabolism in the lateral hypothalamic area (LHA) were investigated. Differential pulse voltammetry with a carbon fiber electrode was used to measure 5-hydroxyindoleacetic acid (5-HIAA), the metabolic product of the serotonin (5-HT). High-performance liquid chromatography with electrochemical detection was also used to analyze these compounds in the cerebrospinal fluid (CSF). The peak in voltammogram at an oxidation potential of +230 mV (P3) was identified as 5-HIAA by pharmacological manipulations that are known to affect 5-HT metabolism. A significant increase in 5-HIAA concentration in the LHA was detected after immobilization. An intraperitoneal injection of 5-hydroxytryptophan (5-HTP; a precursor of 5-HT) increased the height of P3, and injection of pargyline prevented the effect of 5-HTP during the course of increasing P3. These results support our previous conclusion that immobilization-induced anorexia might be mediated through activation of serotonergic mechanisms in the LHA.