Diagnostic approach to neurotransmitter monoamine disorders: experience from clinical, biochemical, and genetic profiles

BACKGROUND AND AIM

To improve the diagnostic work-up of patients with diverse neurological diseases, we have elaborated specific clinical and CSF neurotransmitter patterns.

METHODS

Neurotransmitter determinations in CSF from 1200 patients revealed abnormal values in 228 (19%) cases. In 54/228 (24%) patients, a final diagnosis was identified.

RESULTS

We have reported primary (30/54, 56%) and secondary (24/54, 44%) monoamine neurotransmitter disorders. For primary deficiencies, the most frequently mutated gene was DDC (n = 9), and the others included PAH with neuropsychiatric features (n = 4), PTS (n = 5), QDPR (n = 3), SR (n = 1), and TH (n = 1). We have also identified mutations in SLC6A3, FOXG1 (n = 1 of each), MTHFR (n = 3), FOLR1, and MTHFD (n = 1 of each), for dopamine transporter, neuronal development, and folate metabolism disorders, respectively. For secondary deficiencies, we have identified POLG (n = 3), ACSF3 (n = 1), NFU1, and SDHD (n = 1 of each), playing a role in mitochondrial function. Other mutated genes included: ADAR, RNASEH2B, RNASET2, SLC7A2-IT1 A/B lncRNA, and EXOSC3 involved in nuclear and cytoplasmic metabolism; RanBP2 and CASK implicated in post-traductional and scaffolding modifications; SLC6A19 regulating amino acid transport; MTM1, KCNQ2 (n = 2), and ATP1A3 playing a role in nerve cell electrophysiological state. Chromosome abnormalities, del(8)(p23)/dup(12) (p23) (n = 1), del(6)(q21) (n = 1), dup(17)(p13.3) (n = 1), and non-genetic etiologies (n = 3) were also identified.

CONCLUSION

We have classified the final 54 diagnoses in 11 distinctive biochemical profiles and described them through 20 clinical features. To identify the specific molecular cause of abnormal NT profiles, (targeted) genomics might be used, to improve diagnosis and allow early treatment of complex and rare neurological genetic diseases.

Neuroprotective effects of HTR1A antagonist WAY-100635 on scopolamine-induced delirium in rats and underlying molecular mechanisms

BACKGROUND

Limited surveys have assessed the performance of 5-hydroxytreptamine receptor 1A and its antagonist WAY-100635 in pharmacological manipulations targeting delirium therapies. The purpose of this paper was to assess the central pharmacological activity of WAY-100635 in a rat model of scopolamine-induced delirium and its underlying mechanism.

RESULTS

A delirium rat model was established by intraperitoneal injection of scopolamine and behavioral changes evaluated through open field and elevated plus maze experiments. Concentrations of monoamines in the hippocampus and amygdalae were detected by high performance liquid chromatography. The effect of WAY-100635 on the recovery of rats from delirium was assessed by stereotactic injection of WAY-100635 and its mechanism of action determined by measuring mRNA and protein expression via real time PCR and western blotting methods. The total distance and the number of crossing and rearing in the elevated plus maze test and the time spent in the light compartment in the dark/light test of scopolamine-treated rats were significantly increased while the percentage of time spent in the open arms was decreased, showing the validity of the established delirium rat model. The measurement of the concentrations of noradrenaline, 3,4-dihydroxyphenylacetic acid, the homovanillic acid, 5-hydroxy-3-indoleacetic acid and serotonin concentrations in the cerebrospinal fluid (CSF) of scopolamine-induced delirium rats were significantly increased. The intra-hippocampus and intra-BLA injections of WAY-100635 improved the delirium-like behavior of rats by significantly reducing the expression of NLRP3 inflammasome and the release of IL1-β and IL8 into CSF.

CONCLUSIONS

Taken together, these findings indicate that WAY-100635 may exert a therapeutic effect on post-operative delirium by controlling neurotransmission as well as suppressing neuroinflammation in the central nervous system.

Behavioural profiles in captive-bred cynomolgus macaques: towards monkey models of mental disorders?

BACKGROUND

To date, experimental and preclinical studies on neuropsychiatric conditions have almost exclusively been performed in experimentally-induced animal models and have only rarely relied upon an ethological approach where animals have been observed in more naturalistic settings. The laboratory species of choice has been the rodent while the potential of more closely-related non-human primates have remained largely underexplored.

METHODS

The present study, therefore, aimed at investigating the possible existence of spontaneous atypical/abnormal behaviours displayed by 40 cynomolgus macaques in captive conditions using an unbiased ethological scan-sampling analysis followed by multifactorial correspondence analysis and a hierarchical clustering.

RESULTS

The study identified five distinct profiles (groups A to E) that significantly differed on several behaviours, body postures, body orientations, gaze directions and locations in the cage environment. We suggest that animals from the low n groups (D and E) present depressive-like and anxious-like symptoms, reminiscent of depressive and generalized anxiety disorders. Inter-individual differences were highlighted through unbiased ethological observations of spontaneous behaviours and associated parameters, although these were not associated with differences in plasma or cerebrospinal fluid levels of either stress-related hormones or monoamines, i.e. in accordance with the human situation.

CONCLUSIONS

No interventional behavioural testing was required to discriminate between 3 typical and 2 atypical ethologically-defined behavioural profiles, reminiscent of certain depressive-like and anxiety-like symptoms. The use of unbiased behavioural observations might, thus, allow the identification of animal models of human mental/behavioural disorders and their most appropriate control groups.

Cerebrospinal fluid biomarker candidates of schizophrenia: where do we stand?

Here, we review the cerebrospinal fluid (CSF) candidate markers with regard to their clinical relevance as potential surrogates for disease activity, prognosis assessment, and predictors of treatment response. We searched different online databases such as MEDLINE and EMBASE for studies on schizophrenia and CSF. Initial studies on cerebrospinal fluid in patients with schizophrenia revealed increased brain-blood barrier permeability with elevated total protein content, increased CSF-to-serum ratio for albumin, and intrathecal production of immunoglobulins in subgroups of patients. Analyses of metabolites in CSF suggest alterations within glutamatergic neurotransmission as well as monoamine and cannabinoid metabolism. Decreased levels of brain-derived neurotrophic factor and nerve growth factor in CSF of first-episode patients with schizophrenia reported in recent studies point to a dysregulation of neuroprotective and neurodevelopmental processes. Still, these findings must be considered as non-specific. A more profound characterization of the particular psychopathological profiles, the investigation of patients in the prodromal phase or within the first episode of schizophrenia promoting longitudinal investigations, implementation of different approaches of proteomics, and rigorous adherence to standard procedures based on international CSF guidelines are necessary to improve the quality of CSF studies in schizophrenia, paving the way for identification of syndrome-specific biomarker candidates.

Determination of neurotransmitter levels in models of Parkinson's disease by HPLC-ECD

Parkinson's disease (PD) is a neurological disorder caused by progressive degeneration of dopaminergic neurons in the nigrostriatal area of the brain. The decrease in dopamine (DA) neurotransmitter levels in the striatum and substantia nigra pars compacta is a neurochemistry hallmark of PD. Therefore, determination of dopamine and its metabolites levels in biological samples provides an important key to understanding the neurochemistry profile of PD. This chapter describes the use of reversed-phase HPLC with electrochemical detection (ECD) for simultaneously measuring monoamine neurotransmitters, including dopamine and its metabolites, norepinephrine as well as serotonin and its metabolite. ECD provides an ultrasensitive measurement, which detects at the picogram level. One run for each sample finishes within 18 min, shows clear chromatographic peaks and a complete separation, and produces excellent precision and reproducibility. Once set up, HPLC-ECD is economic and efficient for analyzing a large number of samples. This method has been broadly used for analyzing a variety of biological samples, such as cerebrospinal fluids, plasma, microdialysis elutes, tissues, and cultured cells. In recent days, it has been reported to be able to detect the dopamine level in a single drosophila head.

Monoamines, BDNF, IL-6 and corticosterone in CSF in patients with Parkinson's disease and major depression

The biochemical basis of major depression (MD) in Parkinson's disease (PD) is largely unknown. To increase our understanding of MD in PD patients, the levels of monoamine metabolites (HVA, 5-HIAA and MHPG), BDNF, orexin-A, IL-6 and corticosterone were examined in cerebrospinal fluid. The analyses were performed in MD patients with (n = 11) and without (n = 12) PD at baseline and after 12 weeks' of treatment with the antidepressant citalopram, and in patients with solely PD (n = 14) at baseline and after 12 weeks. The major findings were that PD patients with MD had significantly lower baseline levels of MHPG, corticosterone and IL-6 when compared to patients with solely MD. In response to citalopram treatment, patients with solely MD exhibited an expected decrease in 5-HIAA and MHPG levels which was not found in PD patients with MD. Moreover, the levels of BDNF and IL-6 were lower in PD patients with MD compared with patients with solely MD after treatment with citalopram. Thus, the biochemical basis and the response to citalopram differ between PD patients with MD and patients with solely MD.

Activation of central nervous system inflammatory pathways by interferon-alpha: relationship to monoamines and depression

BACKGROUND

Interferon (IFN)-alpha has been used to study the effects of innate immune cytokines on the brain and behavior in humans. The degree to which peripheral administration of IFN-alpha accesses the brain and is associated with a central nervous system (CNS) inflammatory response is unknown. Moreover, the relationship among IFN-alpha-associated CNS inflammatory responses, neurotransmitter metabolism, and behavior has yet to be established.

METHODS

Twenty-four patients with hepatitis C underwent lumbar puncture and blood sampling after approximately 12 weeks of either no treatment (n = 12) or treatment with pegylated IFN-alpha 2b (n = 12). Cerebrospinal fluid (CSF) and blood samples were analyzed for proinflammatory cytokines and their receptors as well as the chemokine, monocyte chemoattractant protein-1 (MCP-1), and IFN-alpha. Cerebrospinal fluid samples were additionally analyzed for monoamine metabolites and corticotropin releasing hormone. Depressive symptoms were assessed using the Montgomery Asberg Depression Rating Scale.

RESULTS

Interferon-alpha was detected in the CSF of all IFN-alpha-treated patients and only one control subject. Despite no increases in plasma IL-6, IFN-alpha-treated patients exhibited significant elevations in CSF IL-6 and MCP-1, both of which were highly correlated with CSF IFN-alpha concentrations. Of the immunologic and neurotransmitter variables, log-transformed CSF concentrations of the serotonin metabolite, 5-hydroxyindoleacetic acid (5-HIAA), were the strongest predictor of depressive symptoms. Log-transformed CSF concentrations of IL-6, but not IFN-alpha or MCP-1, were negatively correlated with log-transformed CSF 5-HIAA (r(2) = -.25, p < .05).

CONCLUSIONS

These data indicate that a peripherally administered cytokine can activate a CNS inflammatory response in humans that interacts with monoamine (serotonin) metabolism, which is associated with depression.

Clinical experiences and biochemical findings with tacrine (THA)

A clinical comparison of tacrine (THA) and placebo was performed in 15 Alzheimer patients using a double blind crossover technique over 4 plus 4 weeks with one drug-free week in between. Treatment results, as evaluated by clinical rating scales and neuropsychological tests, were mostly negative. Side effects were few, except for elevation liver enzymes which occurred in one third of the patients. CSF levels of the monoamine metabolites HVA and 5-HIAA increased on tacrine as evidence for activation of dopamine and serotonin pathways through cholinergic receptors. Pharmacokinetic investigations showed that the oral bioavailability of tacrine was low and greatly varying between subjects. Patients with high bioavailability of the drug tended to improve more, and also to have more liver enzyme elevations, than those with low bioavailability. A gel preparation for rectal administration was manufactured for comparison of plasma levels attained during one week's treatment with levels attained with oral capsules. Preliminary results indicate that the dose of tacrine can be reduced to 50 per cent when administered rectally, probably as by this route the rapid first-pass metabolism of the drug in the liver is diminished. A clinical trial of tacrine via the rectal route would be justified as this could decrease the number of patients with liver side effects and increase the number of patients improving on the treatment.

Discrimination of Alzheimer patients responding to cholinesterase inhibitor therapy

We have studied whether it is possible to discriminate responders to tacrine treatment from patients nonresponsive to tacrine in Alzheimer's disease. The results indicate that mildly demented patients will most likely gain a benefit of tacrine treatment. Neuropsychological tests on attention and working memory after a single dose of tacrine might be useful as well as a single dose pharmaco-EEG in discriminating responders to treatment.

Monoamine metabolites level in CSF is related to the 5-HTT gene polymorphism in treatment-resistant depression

The serotonin (5-hydroxytryptamine) transporter (5-HTT) is considered to affect the pathogenesis of mood disorders. Large number of genetic association studies between 5-HTT functional polymorphisms and vulnerability of mood disorders and therapeutic response to antidepressants has been carried out. We investigated the influence of 5-HTT-linked polymorphic region (5-HTTLPR) and 5-HTT 17 bp variable number of tandem repeat polymorphism (5-HTTVNTR) polymorphisms on concentrations of monoamine metabolites in cerebrospinal fluid (CSF) among treatment-resistant patients with mood disorders. Subjects were 119 Swedish patients with persistent mood disorders and 141 healthy subjects. In 112 of these patients, we measured 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol in CSF. Genotyping for 5-HTT polymorphisms from genomic DNA was carried out by PCR. There was no significant difference in allele/genotype frequency between patients and healthy subjects. In patients with mood disorders, we found significant difference in mean 5-HIAA concentration between 5-HTTLPR genotypes (p=0.03). Although the 5-HIAA concentration showed a tendency to be higher in short (S) carriers than in non-S carriers of the 5-HTTLPR in patients (p=0.06), when considering patients with major depressive disorder (MDD), the 5-HIAA concentration was significantly higher among S carriers than among non-S carriers (p=0.02). Moreover, the 5-HIAA concentration was higher in S/S subjects compared to long (L)/L (p=0.0001) and L/S (p=0.002) subjects in patients with MDD. Similarly, there was higher HVA concentration in S/S subjects compared to L/L (p=0.002) and L/S subjects (p=0.002). There was no effect of 5-HTTVNTR. Our findings show that the 5-HTTLPR polymorphism affects 5-HIAA and HVA concentrations among treatment-resistant patients with mood disorders.

Association between thyroid hormone levels and monoaminergic neurotransmission during surgery

BACKGROUND

Human studies assessing thyroid hormone metabolism in relation to brain monoaminergic activity in vivo are scarce. The few studies that do exist suggest significant associations between thyroid function and monoaminergic activity, but the cause-and-effect relationships are far from elucidated.

METHODS

We simultaneously collected cerebrospinal fluid (CSF) and serum samples from 35 patients undergoing orthopaedic surgery before, 3h after and the morning after interventions and performed analyses for thyroid hormones and monoamine metabolites.

RESULTS

At baseline, the CSF 3-methoxy-4-hydroxyphenylglycol concentrations were significantly correlated to the serum T(3)/T(4) ratio (rho=0.41, p=0.017). During surgery, serum thyroid hormones and the T(3)/T(4) ratio decreased (p<0.0001), while the CSF T(3)/T(4) ratio increased (p=0.0009). There were no correlations between serum and CSF levels of T(3) and T(4) at any of the samplings. Strong correlations were noted between baseline CSF thyroid hormone concentrations and subsequent increases in CSF 5-hydroxyindoleacetic acid (5-HIAA), and homovanillinic acid (HVA), but not vice versa.

CONCLUSIONS

Thyroid hormone levels in serum and CSF during stress seem to be distinctly regulated. Baseline thyroid hormone activity may facilitate changes in brain monoaminergic neurotransmission in response to stress.

[Central hypotensive effect involving neurotransmitters of long-term administration of taurine to stroke-prone spontaneously hypertensive rat]

BACKGROUND

Taurine is an inhibitory neurotransmitter or neuromodulator that reduces blood pressure when systemically or centrally administered. We studied the central hypotensive effects of long-term oral taurine administration.

METHODS

Arterial blood pressure was measured after delivering an intracisternal injection of 100 mg x 20 microl(-1) or 200 microg x 20microl(-1) of taurine in normal saline, or 20 micro1 normal saline to anesthetized Sprague-Dawley rats. Drinking water containing 3% taurine was administered to stroke-prone spontaneously hypertensive rats (SHRSP) from the age of 4 weeks. Amino acids and monoamine neurotransmitters in the cerebrospinal fluid were measured at 8, 12, 16, 18 weeks of age in taurine treated SHRSP and normotensive Wistar Kyoto rats (WKY) and in untreated SHRSP using high performance liquid chromatography.

RESULTS

Intracisternal injections of taurine caused a dose dependent decrease in arterial blood pressure. Although concentrations of taurine decreased in treated SHRSP rats in an age-related manner, the drug persistently suppressed the development of hypertension. The values of excitatory amino acids and GABA, norepinephrine, NMN, dopamine metabolites, serotonin and its metabolite were lower in taurine-treated SHRSP than those in untreated SHRSP.

CONCLUSIONS

Taurine reduces blood pressure through not only direct inhibition of the cardiovascular center in the medulla, but also by reducing brain monoamine concentrations.

CSF monoamine metabolites and lethality of suicide attempts in depressed patients with alcohol dependence

BACKGROUND

Alcohol dependence (alcoholism) and major depressive disorder are frequently comorbid and are risk factors for suicidal behavior. Monoaminergic abnormalities have been implicated in the pathophysiology of depression, alcohol dependence, and suicidal behavior. Lower cerebrospinal fluid (CSF) 5-hydroxyindolacetic acid (5-HIAA) levels are associated with higher lethality of suicide attempts in major depression and predict a higher rate of future suicide. We sought to study the relationship of CSF monoamine metabolites to lethality of suicidal acts in depressed subjects with comorbid alcoholism.

METHODS

We compared 16 high- and 16 low-lethality drug-free depressed suicide attempters with comorbid alcoholism. Subjects were free from any substance use disorder for at least two months. Demographic and clinical parameters, and CSF 5-HIAA, homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) levels were examined.

RESULTS

The two groups did not differ with regard to the demographic characteristics. CSF 5-HIAA levels were lower in high-lethality attempters compared to low-lethality attempters. There were no group difference in CSF HVA or MHPG levels.

CONCLUSION

Higher lethality of suicidal behavior in depressed patients with alcoholism is related to lower serotonergic activity.

Serial neurochemical measurement of cerebrospinal fluid during the human sexual response cycle

Recent studies examining the neuroendocrine response pattern underlying the human sexual response cycle revealed transient activation of the sympathoadrenal system and a substantial, long-lasting increase in plasma prolactin concentrations following orgasm in men and women. Prolactin has been discussed as being part of a feedback mechanism that signals centers in the central nervous system, such as the dopaminergic system controlling sexual arousal. To further elucidate the central role of neuropeptides, biogenic monoamines and neurotransmitters in human sexual behavior, a serial cerebrospinal fluid (CSF)-sampling technique was implemented using a previously established experimental paradigm for sexual activity in a laboratory setting. In parallel with peripheral endocrine measures, lumbar CSF was drawn via an indwelling spinal catheter during the sexual response cycle in 10 healthy males and 10 age-matched controls, and analysed for prolactin, oxytocin, biogenic monoamines and/or their metabolites as well as inhibitory and excitatory neurotransmitter concentrations. Parallel to raised peripheral sympathetic activity, norepinephrine also increased in CSF during audiovisual, masturbation-induced sexual arousal and orgasm, and remained elevated for the remainder of the session (F(4,72) = 8.79, P = 0.000). In contrast, none of the other measures, in particular prolactin and dopamine or its metabolites, reflected significant alteration. In conclusion, the human sexual response cycle is characterized by an increase in sympathetic activity in plasma and CSF, and by pronounced secretion of plasma prolactin after orgasm. However, alterations in dopaminergic or peptidergic activity are not found in lumbar CSF, possibly due to local and restricted release in diencephalic and mesencephalic brain regions.

Psychopharmacology of maternal separation anxiety in vervet monkeys

Maternal separation in non-human primates has been proposed as a model of early adversity. The symptoms of separation anxiety were studied in vervet monkeys, during the weaning period, when psychotropic medications were administered. The control group received a normal diet and treatment groups received citalopram, reboxetine or lamotrigine in their food daily. Treatment was given for 7 weeks starting 1 month prior to weaning. Behavior was recorded twice weekly for 8 weeks, and was rated for anxiety and depression. Cerebrospinal fluid was collected at the beginning and end of the trial and analyzed for monoamines and metabolites using High Performance Liquid Chromatography. Citalopram pretreatment prevented the reduction of affiliation behavior and reduced stereotypies after weaning, and both citalopram and reboxetine abolished the increase in activity seen in control monkeys after weaning, but no statistically significant differences were found between groups. Citalopram pretreatment also significantly increased noradrenaline and 5-hydroxyindolacetic acid (5-HIAA) levels and reboxetine significantly decreased dopamine levels over time. The 5-HIAA levels of reboxetine and lamotrigine treated monkeys were significantly lower than that of the control group at the end of the trial. Although limited by a small sample size, this study demonstrates the possibility of investigating the psychopharmacology of early adversity in a non-human primate model.

CSF monoamine patterns in pathological gamblers and healthy controls

Previous reports on compounds in the cerebrospinal fluid (CSF) of pathological gamblers have focused on disturbed NA, DA and 5-HT function in the central nervous system. We have analysed precursors, transmitters and transmitter metabolites in 3 x 6 ml of CSF obtained from one female and 11 male pathological gamblers and 11 healthy male controls lumbar punctured at the L4-5 level after 8 h of fasting without preceding strict bedrest. Pathological gamblers displayed lower CSF levels of tryptophan and 5-HT while the opposite was the case for 5-HIAA, tyrosine, DA, HVA, DOPAC and HMPG. In contrast to previous studies, the NA level did not differ between pathological gamblers and healthy controls. A disrupted CSF gradient was noted for tryptophan, 5-HT, DA, HVA, DOPAC, NA and HMPG, but only in pathological gamblers. A disrupted gradient was found for 5-HIAA in both pathological gamblers and healthy controls. The results are in line with the presence of altered indoleamine and catecholamine function in pathological gamblers as well as an altered CSF transport from the brain to the lumbar compartment in such gamblers.

Acute response to intracisternal bupivacaine in patients with refractory pain of the head and neck

Continuous intracisternal infusion of bupivacaine for the management of intractable pain of the head and neck is effective in controlling pain in this patient group. With the catheter tip being located at the height of the C1 vertebral body, autonomic regulatory information may also be influenced by the infusion of bupivacaine. By combining direct sampling of cerebrospinal fluid (CSF), via a percutaneously placed catheter in the cisterna magna, with a noradrenaline and adrenaline isotope dilution method for examining sympathetic and adrenal medullary activity, we were able to quantify the release of brain neurotransmitters and examine efferent sympathetic nervous outflow in patients following intracisternal administration of bupivacaine. Despite severe pain, sympathetic and adrenal medullary activities were well within normal range (4.2 +/- 0.6 and 0.7 +/- 0.2 nmol min(-1), respectively, mean +/-S.E.M.). Intracisternal bupivacaine administration caused an almost instantaneous elevation in mean arterial blood pressure, increasing by 17 +/- 7 mmHg after 10 min (P < 0.01). Heart rate increased in parallel (17 +/- 5 beats min(-1)), and these changes coincided with an increase in sympathetic nervous activity, peaking with an approximately 50% increase over resting level 10 min after injection (P < 0.01). CSF levels of GABA were reduced following bupivacaine (P < 0.05). CSF catecholamines and serotonin, and EEG, remained unaffected. These results show that acutely administered bupivacaine in the cisterna magna of chronic pain sufferers leads to an activation of the sympathetic nervous system. The results suggest that the haemodynamic consequences occur as a result of interference with the neuronal circuitry in the brainstem. Although these effects are transient, they warrant caution at the induction of intracisternal local anaesthesia.

Treatment enhances ultradian rhythms of CSF monoamine metabolites in patients with major depressive episodes

Unipolar and bipolar depressions show abnormal behavioral manifestations of ultradian (less than 24 h) rhythms, but abnormal rhythms of the central neurotransmitters thought to be important for depression pathophysiology (eg dopamine (DA) and serotonin (5-HT)) have not been shown in this time frame. Since antidepressant treatments normalize disrupted rhythms in depression (eg rapid-eye-movement sleep and hormonal rhythms), we hypothesized that depression-related changes in ultradian oscillations of DA and 5-HT might be revealed during antidepressant treatment. Cerebrospinal fluid (CSF) samples collected q10 min for 24 h in 13 patients experiencing major depressive episodes (MDE) before and after treatment for 5 weeks with sertraline or bupropion were assayed for levels of homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA), and their ratio was calculated. Data were analyzed in the frequency domain using Fourier transforms and multivariate permutation testing. Antidepressant treatments were associated with decreased variance for 5-HIAA, increased variance for HVA, and markedly increased variance for the HVA : 5-HIAA ratio (p<0.05, p<0.02, and p<0.003, respectively). With treatment, the correlations between 5-HIAA and HVA weakened (p=0.06). Power spectral density (PSD-the Fourier magnitude squared) of the 5-HIAA signals at periods of 1.75 and 3.7 h (both p<0.05) decreased, while circadian cycling of HVA levels (p<0.05) and of the ratio (p<0.005) increased after treatment. The PSD of the full-length HVA : 5-HIAA ratio series after treatment increased in rapid variability (20-103 min periods, p<0.05). Spectrographic windowing demonstrated a focal span of enhanced HVA : 5-HIAA ratio variability following antidepressant treatment, in an approximately 84-min period through the evening (p<0.05). Periodic neurotransmitter relationships in depressed patients were altered by treatment in this analysis of a small data set. This may represent a baseline abnormality in the regulation of periodic functions involved in the depression pathophysiology, but it could also be due to an unrelated antidepressant effect. Further studies including comparisons with healthy subject data are in progress.

The effects of a selective dopamine D2 receptor agonist on behavioral and pathological outcome in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated squirrel monkeys

In this study, we investigated antiparkinsonian activity of the novel, highly selective dopamine D(2) receptor agonist sumanirole compared with two clinically effective dopaminergic therapies in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) primate model of Parkinson's disease. Squirrel monkeys were rendered parkinsonian by chronic administration of MPTP and subsequently dosed with vehicle, L-DOPA plus carbidopa (L-DOPA), ropinirole, or sumanirole over a duration of 8 weeks. Antiparkinsonian effects measured with a parkinsonian primate rating scale (PPRS) showed that sumanirole elicited improved functional outcome compared with vehicle. The dopamine D2/D3 agonist ropinirole improved behavioral outcome similar to sumanirole, whereas L-DOPA treatment yielded the most significant symptomatic improvement. The relative rank of therapies that elicited normalization of PPRS was L-DOPA > sumanirole; ropinirole did not normalize PPRS in any of the treated monkeys. Dyskinesias were present with L-DOPA treatment but were not observed in sumanirole-, ropinirole-, or placebo-treated primates. Pathologically, all MPTP-treated animals displayed neurodegeneration of dopaminergic neurons in the substantia nigra pars compacta and reactive astrocytosis. Neurons immunoreactive with antibodies to the nuclear transcription factor DeltaFosB were most significantly increased in the striatum of L-DOPA-treated monkeys. These results suggest that sumanirole can exert antiparkinsonian effects similar to L-DOPA without the behavioral and morphological consequences of the latter.

Effect of vagus nerve stimulation on cerebrospinal fluid monoamine metabolites, norepinephrine, and gamma-aminobutyric acid concentrations in depressed patients

BACKGROUND

Vagus nerve stimulation (VNS) has shown promising antidepressant effects in treatment-resistant depression, but the mechanisms of action are not known. Cerebrospinal fluid (CSF) studies in epilepsy patients show that VNS alters concentrations of monamines and gamma-aminobutyric acid (GABA), neurotransmitter systems possibly involved in the pathogenesis of depression.

METHODS

Twenty-one adults with treatment-resistant, recurrent, or chronic major depression underwent standardized lumbar puncture for collection of 12 mL CSF on three separate but identical procedure days during participation in the VNS D-02 clinical trial. All subjects remained on stable regimens of mood medications. Collections were made at baseline (2 weeks after surgical implantation but before device activation), week 12 (end of the acute-phase study), and week 24. Cerebrospinal fluid concentrations of norepinephrine (NE), 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) were determined with high-performance liquid chromatography. Concentrations of GABA were assayed with mass spectrometry.

RESULTS

Comparison of sham versus active VNS revealed a significant (mean 21%) VNS-associated increase in CSF HVA. Mean CSF concentrations of NE, 5-HIAA, MHPG, and GABA did not change significantly. Higher baseline HVA/5-HIAA ratio predicted worse clinical outcome.

CONCLUSIONS

Although several of the CSF neurochemical effects we observed in this VNS study were similar to those described in the literature for antidepressants and electroconvulsive therapy, the results do not suggest a putative antidepressant mechanism of action for VNS.

Difficulties in establishing reference intervals for special fluids: the example of 5-hydroxyindoleacetic acid and homovanillic acid in cerebrospinal fluids

Biochemical measurements in “special fluids” are complicated with the problem of reference intervals. Reference intervals are difficult to establish for these types of samples since they are usually only collected in patients with clinical suspicion of disease. Determination of neurotransmitter metabolites in cerebrospinal fluid illustrates this difficulty. This paper will review the factors and circumstances that have been identified or are suspected to modifythe concentration of 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) in cerebrospinal fluid. In addition to obvious parameters such as age-related variation that can affect the concentration of 5-HIAA and HVA in cerebrospinal fluid, a varietyof other factors can explain the wide range of “control” group sizes reported in the literature. Reference intervals must take into account the purpose of cerebrospinal fluid examinations, whether they be prospective studies to explore physio-pathologic relationships or for diagnostic purposes. In the latter case, certain neurological disorders cannot be excluded if a single measured value is within the reference interval.

Tyrosine hydroxylase deficiency causes progressive encephalopathy and dopa-nonresponsive dystonia

Tyrosine hydroxylase (TH) is the key enzyme in the biosynthesis of the catecholamines dopamine, epinephrine, and norepinephrine. Recessively inherited deficiency of TH was recently identified and incorporated into recent concepts of genetic dystonias as the cause of recessive Dopa-responsive dystonia or Segawa's syndrome in analogy to dominantly inherited GTP cyclohydrolase I deficiency. We report four patients with TH deficiency and two with GTP cyclohydrolase I deficiency. Patients with TH deficiency suffer from progressive infantile encephalopathy dominated by motor retardation similar to a primary neuromuscular disorder, fluctuating extrapyramidal, and ocular and vegetative symptoms. Intellectual functions are mostly compromised. Prenatally disturbed brain development and postnatal growth failure were observed. Treatment with levodopa ameliorates but usually does not normalize symptoms. Compared with patients with dominantly inherited GTP cyclohydrolase I deficiency, catecholaminergic neurotransmission is severely and constantly impaired in TH deficiency. In most patients, this results not in predominating dystonia, a largely nondegenerative condition, but in a progressive often lethal neurometabolic disorder, which can be improved but not cured by L-dopa. Investigations of neurotransmitter defects by specific cerebrospinal fluid determinations should be included in the diagnostic evaluation of children with progressive infantile encephalopathy.

The activity in the CNS catecholaminergic systems covaries with thyroid hormone metabolism in humans

Do the CNS monoaminergic (MA) systems regulate thyroid hormone metabolism in humans? In 23 unmedicated, male, violent offenders without signs of thyroid disease, we found positive correlations between the catecholaminergic CSF metabolites HVA and MHPG and the peripheral T3/T4 ratio (rho=0.55, p=0.010 and 0.51, p=0.018), indicating that increased activity in the brain MA systems, especially the dopaminergic, is associated with increased peripheral thyroid hormone activity.

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.

Self-rated aggression and cerebral monoaminergic turnover. Sex differences in patients with persistent depressive disorder

OBJECTIVE

Outward-directed violence and impulsivity in humans and primates has frequently been related to abnormal brain monoaminergic turnover. Self-rated aggression is likely to be clinically relevant,and its psychobiological basis needs investigation.

SUBJECTS

Sixty-six patients (40 women and 26 men) with persistent depressive disorder (PDD) were compared with 497 control subjects from the general Swedish population.

METHODS

We administered the Aggression Questionnaire - Revised Swedish Version (AQ-RSV) to patients and control subjects. In patients, CSF 5-hydroxyindoleacetic acid (5-HIAA) and 3-methoxy-5-hydroxyphenylglycol (MHPG) in CSF were analyzed. Total Aggression score and Aggression subfactors 'Physical Aggression','Verbal Aggression','Anger', and 'Hostility'were correlated with CSF concentrations of 5-hydroxyindoleacetic acid (5-HIAA),and 3-methoxy-5-hydroxyphenylglycol (MHPG).

RESULTS

Overall, Hostility was positively related to CSF MHPG (t=2.27, p=0.015). Split by sex,Hostility was related with 5-HIAA in males (r=0.62,p=0.003),and with MHPG in females (r=0.38, p=0.03). Comparing self rated aggression with age- and sex-matched data from the general Swedish population, the most prominent deviation was increased Hostility score among PDD patients. Among patients, all aggression factors were nominally higher in women than in men, with the most pronounced sex difference in Hostility (t=-1.89, p=0.04).

CONCLUSIONS

Results suggest a clinically meaningful sex difference in a positive relationship between hostility and serotonergic/noradrenergic turnover in PDD patients.

Amino acids and biogenic amines in cerebrospinal fluid of patients with Parkinson's disease

To study changes in amino acid metabolism and biogenic amines in Parkinson's disease, we set up a prospective study and measured biogenic amines, their main metabolites, and 22 different amino acids, in cerebrospinal fluid of Parkinson's disease patients (n = 24) and age-matched controls (n = 30). A trend toward higher dopamine levels in Parkinson's disease patients was interpreted as an effect of treatment with levodopa and/or selegiline. Significantly lower concentrations of the dopamine metabolite 3,4-dihydroxyphenylacetic acid in the Parkinson's disease group might reflect dopaminergic cell loss. Our results revealed decreased serotonin catabolism that was interpreted as an effect of treatment with selegiline. Whereas all amino acid levels were unchanged, taurine was significantly lower in Parkinson's disease patients. Studies showed that taurine exerts a trophic action on the central nervous system. In this view, decreased taurine in a neurodegenerative disorder as Parkinson's disease deserves attention.

Two NOTCH4 polymorphisms and their relation to schizophrenia susceptibility and different personality traits

BACKGROUND

Recently, linkage disequilibrium mapping of the major histocompatibility complex region on the short arm of human chromosome 6 suggested that the NOTCH4 locus is highly associated with schizophrenia.

OBJECTIVES AND METHODS

We analysed two polymorphisms in this gene in Swedish schizophrenic patients ( =74) and control subjects ( =135). The NOTCH4 variants were also analysed in schizophrenic patients with regard to subdiagnosis, age at first hospitalization, abuse/dependence of alcohol, solvents, or drugs, previous suicide attempts, extrapyramidal symptoms, treatment with anticholinergic drugs, and response to anti-psychotic drug treatment. Control subjects were scrutinized with regard to personality, another partially heritable trait suggested being of importance in schizophrenia. In addition, two intermediate endophenotypes suggested being of importance in schizophrenia, dopamine D(2) receptor density in striatum and monoamine metabolites in cerebrospinal fluid, respectively, were investigated with regard to the two NOTCH4 variants.

RESULTS

There was no significant association between the patients and the controls for the two investigated polymorphisms neither for the parameters analysed in the schizophrenia material. The NOTCH4 SNP2 variant, an A-->G substitution, was associated with the Karolinska Scales of Personality Irritability scale. The NOTCH4 (CTG)(n) variant was associated with the revised NEO personality inventory Extraversion and Activity (E4) scales. However, after correction for multiple testing, no difference remained significant. The results for the endophenotypes and the polymorphisms were non-significant.

CONCLUSIONS

The present study does not support that the investigated NOTCH4 variants have a major influence on susceptibility to schizophrenia or related neurobiological traits.

CSF monoamine metabolites and MRI brain volumes in alcohol dependence

Correlations between cerebrospinal fluid (CSF) concentrations of monoamine metabolites (MAM) and brain structure have been described in schizophrenia, but not in alcoholism. To investigate the relationship between monoaminergic transmission and brain structure in alcoholism, the metabolites of dopamine (homovanillic acid, HVA), norepinephrenine (3-methoxy-4-hydroxyphenylethyleneglycol, MHPG) and serotonin (5-hydroxyindoleacetic acid, 5-HIAA) were measured in lumbar CSF in 54 alcohol-dependent patients and 20 healthy subjects. The volumes of the cerebrum, total grey and white matter, total and ventricular CSF, left and right hippocampus, and corpus callosum area were measured with MRI. MHPG and age were positively correlated in alcoholic women. The MAM concentrations were not significantly correlated with the MRI volumes in the subject categories. There were no differences in MAM across subjects defined by diagnosis and gender, age of onset of alcoholism or comorbidity of psychiatric disorders. Total CSF, cerebrum, and white and grey matter tissue volumes differed between patients and healthy subjects. The greatest difference was the white matter reduction in alcoholic women. In alcoholic women and men, monoaminergic neurotransmission measured by the CSF MAM HVA, MHPG, and 5-HIAA is not significantly correlated with the size of different brain structures.

Intrathecal transplantation of neuroblastoma cells decreases heat hyperalgesia and cold allodynia in a rat model of neuropathic pain

Intrathecal grafting of cells as biological pumps to deliver monoamines, endorphins, and/or trophic factors, has been shown to be effective in treating chronic pain both in experimental animals and in clinical trials. We have tested whether intrathecal implantation of neuroblastoma cells reduces heat hyperalgesia and cold allodynia in a rat model of neuropathic pain induced by chronic constriction injury (CCI) of the sciatic nerve. Behavioral tests and cerebrospinal fluid (CSF) collection were performed before CCI, 1 week later (after which, vehicle or NB69 cells were intrathecally injected) and at 4, 7, and 14 days post-injection. Both CSF sampling and injection of the cells were performed by direct lumbar puncture. Intrathecal grafting of 4 x 10(6) NB69 neuroblastoma cells reduced to basal levels the nociceptive response to heat in nerve-injured hindpaws, while the response of control limbs remained unchanged. Similarly, the allodynic response to cold elicited by acetone evaporation decreased in the animals implanted with NB69 cells. An increase in the concentrations of dopamine and serotonin metabolites of around 150% was observed in the CSF of animals that received grafts of NB69 cells. These data suggest that the monoamines released by NB69 cells in the intrathecal space produce analgesia to neuropathic pain in rats.

Monoamine metabolism and sympathetic nervous activation following subarachnoid haemorrhage: influence of gender and hydrocephalus

Subarachnoid haemorrhage is a serious condition, often accompanied by cerebral vasospasm and hydrocephalus, which may result in delayed cerebral ischaemia and neurological deterioration. While the mechanisms responsible remain unknown, activation of the sympathetic nervous system, leading to elevated levels of circulating catecholamines is, at least in part, implicated. In this study, we sought to examine the importance of sympathetic nervous activation and its relation to brain monoaminergic neurotransmission in 25 patients following subarachnoid haemorrhage by examining plasma and cerebrospinal fluid levels of the catecholamines noradrenaline, adrenaline and dopamine, and their metabolites. Total body sympathetic activity was concurrently assessed using isotope dilution methodology. In the early phase following subarachnoid haemorrhage patients exhibited markedly elevated rates of spillover of noradrenaline to plasma (9.11 +/- 1.12 vs. 3.39 +/- 0.26 nmol/min, p < 0.01), with rates being higher in those patients in whom hydrocephalus developed (11.15 +/- 1.40 vs. 7.90 +/- 1.41 nmol/min, p = 0.05). The degree of sympathetic nervous activation tended to be higher in females compared with males. Lower cerebral perfusion pressures were observed in those patients in whom cerebrospinal fluid concentrations of noradrenaline and dopamine metabolites were high. A marked sympathetic nervous activation, more pronounced in women and in those with hydrocephalus, occurs following subarachnoid haemorrhage. The diminished cerebral perfusion seen following subarachnoid bleeding may occur as a result of activation of central catecholaminergic neurones.

[The research on monoamine neurotransmitters changes in plasma and cerebrospinal fluid in patients with persistent vegetative state]

AIM

To study the relationships between the pathogenesis of persistent vegetative state (PVS) and the levels of monoamine neurotransmitters in plasmas and cerebrospinal fluids (CSFs) in patients with PVS.

METHODS

The high-pressure liquid chromatography (HPLC) was used to detect.

RESULTS

It was found that the level of dopamine (1.95 +/- 0.99) was significantly increased in plasma compared with the control (1.16 +/- 0.47) (P < 0.05), but the levels of 5-HT, TYR, TRP, GABA of plasma were insignificantly changed. In cerebrospinal fluid, the level of DA was insignificantly changed, and the level of 5-HT (0.49 +/- 0.32) was significantly decreased compared with the control (1.02 +/- 0.35) (P < 0.05), but the levels of TYR (1.36 +/- 0.11), TRP (0.63 +/- 0.40), GABA (1.15 +/- 0.61) were significantly increased respectively compared with the controls (0.40 +/- 0.24; 0.29 +/- 0.22; 0.37 +/- 0.45) (P < 0.05; P < 0.05; P < 0.01). The levels of GABA and DA in plasma were significant correlated (P < 0.05), and GABA and DA in CSF were also significant correlated (P < 0.01).

CONCLUSION

The results of this study suggested that PVS is related to the decrease of 5-HT in CSF and the increase of DA in plasma.

Central nervous system monoamine correlates of social dominance in cynomolgus monkeys (Macaca fascicularis)

Social dominance is a fundamental component of both human and nonhuman primate sociality. However, its neurobiological correlates remain incompletely understood. We evaluated the association between dominance status and monoamine metabolite concentrations in cisternal cerebrospinal fluid (CSF) in adult male (n = 25) and female (n = 21) cynomolgus macaques (Macaca fascicularis) housed in unisexual social groups. Concentrations of the metabolites of dopamine (homovanillic acid [HVA]), norepinephrine (3-methoxy-4-hydroxyphenylglycol [MHPG]) and serotonin (5-hydroxyindoleacetic acid [5-HIAA]) were assayed. Dominant monkeys, both males and females, had significantly higher CSF HVA concentrations than did subordinates (p values <.05). Among males, but not females, dominants also had lower CSF 5-HIAA than subordinates (p <.05). The Dominance-HVA association observed here is consistent with recent speculation that social extraversion, a dominance-related personality trait in humans, may also reflect heightened central nervous system dopaminergic activity.

The role of central serotonergic dysfunction in the aetiology of premenstrual dysphoric disorder: therapeutic implications

Premenstrual dysphoric disorder (PMDD), as defined in DSM-IV, is a mood disorder. One of the leading theories for the pathogenesis of mood disorders is dysfunction of the serotonergic system. An increasing database suggests that serotonergic dysfunction also characterises PMDD. Evidence that treatments which enhance serotonergic function are beneficial in reducing the symptoms of PMDD support this hypothesis. Indeed, most of the evidence from baseline studies suggests predominantly a serotonergic rather than a noradrenergic or dopaminergic dysfunction. Challenge studies further support this hypothesis. These findings of neurotransmitter dysfunction are more consistent than those of other neuroendocrine abnormalities for example. Based on treatment studies, a selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitor, fluoxetine, has been approved for use in PMDD by the US Food and Drug Administration.

Therapeutic effect and mechanism of repetitive transcranial magnetic stimulation in Parkinson's disease

The therapeutic effect of repetitive transcranial magnetic stimulation (rTMS) on clinical performance was assessed by a double-blind study in 9 patients with Parkinson's disease (PD). Nine other patients underwent sham stimulation as controls. The modified Hoehn and Yahr (H&Y) staging scale, the Schwab and England Activities of Daily Living (ADL) scale, and the Unified Parkinson's disease rating scale (UPDRS) were used to assess changes of clinical performance. Patients were assessed prior to and following 2 months of rTMS. In addition, the mechanism of rTMS was investigated by dopamine and homovanillic acid (HVA) in the lumbar cerebrospinal fluid (CSF) of 17 patients before and after therapeutic rTMS for three or four months. rTMS was applied manually to the frontal areas 60 times per session, i. e., 30 times per side using a large circular coil, a pulse intensity of 700 V, and a frequency of 0.2 Hz. Sessions were continued once a week for 2 months. The 9 control patients showed no changes of symptoms between the initial evaluation and that after 2 months of sham rTMS. In contrast, all 9 patients receiving rTMS showed a significant decrease of the modified H&Y and UPDRS scores after 2 months, while the Schwab and England ADL Scale scores increased significantly. In the second CSF sample from patients receiving rTMS, HVA showed a significant decrease These results suggest that rTMS is beneficial for the symptoms of Parkinson's disease and that it may act via inhibition of dopaminergic systems.

Cerebrospinal fluid markers in children with cerebral white matter abnormalities

Disorders of the cerebral white matter in children constitute a heterogeneous group and the diagnostic work is often complicated. Clinical and radiological characteristics can provide diagnostic clues but there is a need for further diagnostic methods. This study focused on assessing neurochemical "markers" in the cerebrospinal fluid considered to reflect damage to white matter components such as myelin and glial cells as well as neurones with their axons and synapses. The aim was to evaluate whether they contributed to the elucidation of pathogenic processes and the direction of further diagnostic efforts. Seventeen of the 26 cases had increased levels of the glial cell marker ganglioside GD3, indicating gliosis, or of the CNS myelin marker sulfatide, indicating myelin disturbance. As signs of disturbed maturation or sustenance, the nerve cell markers GD1 b, GT1 b and total gangliosides were reduced, as was the synapse marker GD1a. Increased 5-HIAA indicated increased serotonergic turnover. Children with an increased level of the axonal marker Tau protein had a progressive disease whereas GD1a was reduced in the progressive group (n = 11). In contrast, GD3 and HVA were increased in the non-progressive group (n = 15). The chemical profiles were found to be useful, in combination with clinical and radiological findings, when investigating children with white matter abnormalities.

Physiological correlates of self-injurious behavior in captive, socially-reared rhesus monkeys

This study examined the relationship between self-injurious behavior (SIB) in rhesus monkeys and several biological variables, including monoamine metabolites in cerebrospinal fluid (CSF) and circulating levels of ACTH, cortisol, and testosterone. Cisternal CSF and blood plasma samples were obtained from 23 individually housed male rhesus macaques, 14 of which had a veterinary record of self-inflicted wounding. CSF samples were analyzed for 5-hydroxyindole-3-acetic acid (5-HIAA), homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG) using isocratic high-performance liquid chromatography with electrochemical detection (HPLC-EC). Plasma samples were analyzed for ACTH, cortisol, and testosterone using commercially available radioimmunoassays (RIAs). Rates of self-directed biting were determined by systematic observation of all monkeys. Monkeys with SIB did not differ from controls in their basal monoamine or gonadal activity. However, the SIB group showed consistently lower mean plasma cortisol levels than the control group. Plasma cortisol was negatively correlated with rates of self-directed biting. These results suggest a persistent dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in monkeys with SIB. It is not yet clear whether this phenomenon of low cortisol represents chronically reduced adrenocortical secretion under basal conditions or a difference in response to the mild stress of capture and chemical restraint. The implications of these findings will be discussed with respect to SIB in humans as well as post-traumatic stress disorder (PTSD), a condition characterized by pituitary-adrenocortical hypoactivity.

Uncoupling of serotonergic and noradrenergic systems in depression: preliminary evidence from continuous cerebrospinal fluid sampling

We used the technique of continuous cerebrospinal fluid (CSF) sampling to test the following hypotheses regarding CNS monoaminergic systems in depression: (1) absolute concentrations of the informational substances tryptophan and 5-hydroxyindoleacetic acid (5-HIAA) are altered in the CNS of depressed patients (2) abnormal rhythms of tryptophan and/or 5-HIAA, or defective conversion of tryptophan to serotonin (5HT), exist in the CNS of depressed patients, and (3) the relationship between the CNS 5HT and norepinephrine (NE) systems is disrupted in depressed patients. We obtained 6-h concentration time series of tryptophan, 5-HIAA, NE, and 3-methoxy-4-hydroxyphenylglycol (MHPG) in the CSF of 10 patients with major depression and in 10 normal volunteers. No significant differences in CSF tryptophan, 5-HIAA, NE, or MHPG concentrations or rhythms were observed between normal volunteers and depressed patients. Neither were there differences in the mean tryptophan-to-serotonin ratio. However, a negative linear relationship was observed between mean concentrations of 5-HIAA and NE in the CSF of the normal volunteers (r = 0.916 [r2 = 0.839], df = 9, P < 0.001) while, in contrast, depressed patients showed no such relationship (r = +0.094 [r2 = 0.00877], df = 9, n.s.). Furthermore, the correlation coefficients expressing the relationship between CSF MHPG and CSF 5-HIAA within the normal and depressed groups were significantly different. These data support the hypothesis that a disturbance in the interaction between the serotonergic and noradrenergic systems can exist in depressive illness in the absence of any simple 5HT or NE deficit or surplus.

Homocysteine, folate, methylation, and monoamine metabolism in depression

OBJECTIVES

Previous studies suggest that folate deficiency may occur in up to one third of patients with severe depression, and that treatment with the vitamin may enhance recovery of the mental state. There are, however, difficulties in interpreting serum and red cell folate assays in some patients, and it has been suggested that total plasma homocysteine is a more sensitive measure of functional folate (and vitamin B12) deficiency. Other studies suggest a link between folate deficiency and impaired metabolism of serotonin, dopamine, and noradrenaline (norepinephrine), which have been implicated in mood disorders. A study of homocysteine, folate, and monoamine metabolism has, therefore, been undertaken in patients with severe depression.

METHODS

In 46 inpatients with severe DSM III depression, blood counts, serum and red cell folate, serum vitamin B12, total plasma homocysteine, and, in 28 patients, CSF folate, S-adenosylmethionine, and the monoamine neurotransmitter metabolites 5HIAA, HVA, and MHPG were examined. Two control groups comprised 18 healthy volunteers and 20 patients with neurological disorders, the second group undergoing CSF examination for diagnostic purposes.

RESULTS

Twenty four depressed patients (52%) had raised total plasma homocysteine. Depressed patients with raised total plasma homocysteine had significant lowering of serum, red cell, and CSF folate, CSF S-adenosylmethionine and all three CSF monoamine metabolites. Total plasma homocysteine was significantly negatively correlated with red cell folate in depressed patients, but not controls.

CONCLUSIONS

Utilising total plasma homocysteine as a sensitive measure of functional folate deficiency, a biological subgroup of depression with folate deficiency, impaired methylation, and monoamine neurotransmitter metabolism has been identified. Detection of this subgroup, which will not be achieved by routine blood counts, is important in view of the potential benefit of vitamin replacement.

Season of birth variations in dimensions of functioning evaluated by the diagnostic interview for borderline patients

In view of recent reports showing that cerebrospinal fluid (CSF) levels of monoamine metabolites exhibit season of birth variations, and that they are also associated with section II (impulse action patterns) of the diagnostic interview for borderline patients (DIB), we analyzed two samples of data to investigate the relationship between the season of birth and the DIB. The first sample comprised 202 patients participating in psychobiological research in Stockholm, and the second sample comprised 130 patients who had committed suicide in Västerbotten in northern Sweden. Those with intermediate score for section II (impulse action patterns) were significantly more likely to have been born during the season October to January in the pooled data, and this tendency persisted in separate analyses for the two samples and for the two diagnostic groups mood disorders and schizophrenia, respectively. Those with high score for section IV (psychosis) were significantly more likely to have been born during February to April in the pooled sample and in the nonschizophrenic group. In the group with schizophrenia, those born during February to April had significantly high scores for section III (affects). These results throw further light on the role of season of birth in suicidology and in psychiatric morbidity.

A promoter polymorphism in the monoamine oxidase A gene and its relationships to monoamine metabolite concentrations in CSF of healthy volunteers

Concentrations of monoamine metabolites (MM) in lumbar cerebrospinal fluid (CSF) have been used extensively as indirect estimates of monoamine turnover in the brain. We investigated possible relationships between a putative functional promoter polymorphism in the monoamine oxidase A (MAOA) gene and CSF concentrations of homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) in healthy volunteers (n=88). Among women (n=37), those carrying at least one copy of the alleles associated with more efficient transcription displayed higher concentrations of HVA (p=0.01) and 5-HIAA (p=0.01). In men (n=51), however, there was a tendency in the opposite direction. The results suggest that MAOA genotypes may participate differentially in the regulation of dopamine and serotonin turnover rates under presumed steady state in the central nervous system. The results should be interpreted with caution until replicated because of the limited sample size.

Developmental changes in cerebrospinal fluid concentrations of monoamine-related substances revealed with a Coulochem electrode array system

The relationship between age and cerebrospinal fluid concentrations of monoamine-related substances, including kynurenine, were investigated using a Coulochem electrode array system, to clarify developmental changes in monoamine-related substances in the human central nervous system. In neurologically normal children, significant inverse correlations with age were observed for the cerebrospinal fluid concentrations of 5-hydroxytryptophan, 5-hydroxyindole-acetic acid, kynurenine, homovanillic acid, 3-methoxy-4-hydroxyphenyl glycol, and 3-O-methyl-dopamine. The concentrations of their precursors, tryptophan and tyrosine, were not related to age. This is the first comprehensive study revealing developmental changes in monoamine-related substances including their precursors and metabolites.

Changes in the cerebrospinal-fluid monoamines in rats with an immunoneutralization of the subcommissural organ-Reissner's fiber complex by maternal delivery of antibodies

The subcommissural organ (SCO) is a brain gland secreting glycoproteins into the cerebrospinal fluid (CSF), where they aggregate forming the Reissner's fiber (RF). By the continuous addition of newly released glycoproteins, RF grows along the cerebral aqueduct, fourth ventricle, and central canal of the spinal cord. At the filum, RF-glycoproteins escape from the central canal and reach the local blood vessels. Despite a century of research, the function of the SCO remains elusive. The aim of the present investigation was to test the hypothesis that RF-glycoproteins, by binding and transporting monoamines out of the CSF, participate in the clearance of these compounds. A protocol was designed that led to the permanent immunoneutralization of the SCO through the maternal delivery of antibodies. This was achieved by transplacental transfer to the fetuses, and through the milk to the pups, of specific antibodies against SCO secretory proteins. The antibodies reached the CSF of the fetuses and pups and blocked the RF formation during the first months of life. Some of these animals died during the first postnatal weeks; those who survived displayed a rise in the CSF concentration of several monoamines, l-DOPA being the one with the highest rise. Adult rats transiently deprived of RF by a single injection of anti-RF antibodies into the CSF showed a transient rise in the CSF concentration of l-DOPA. All these results support the hypotheses that the SCO-RF complex participates in the clearance of monoamines from the CSF.

HTR2C Cys23Ser polymorphism in relation to CSF monoamine metabolite concentrations and DSM-III-R psychiatric diagnoses

BACKGROUND

Heritable variation in brain monoaminergic activity has been suggested to lead to interindividual differences in vulnerability to alcoholism, and many other behavioral disorders. We evaluated if a functional Cys23Ser polymorphism in the 5-HT2C receptor gene, the principal serotonin receptor in the brain, contributes to variation in serotonin, norepinephrine and dopamine activity, as indexed by their major metabolite concentrations in cerebrospinal fluid (CSF). Genotype-monoamine metabolite concentration associations were subsequently correlated to risk for alcoholism.

METHODS

The study sample consisted of unrelated Finnish males, including 214 alcoholic, violent offenders and 222 population controls who were interviewed using the Structured Clinical Interview for DSM-III-R, blind rated for psychiatric diagnoses and typed for the HTR2C Cys23Ser polymorphism. CSF concentrations of 5-hydroxyindoleacetic acid (5-HIAA), the major metabolite of serotonin, 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG), the major metabolite of norepinephrine, and homovanillic acid (HVA), the major metabolite of dopamine were available from 195 individuals.

RESULTS

The major finding in this study was that HTR2C CysSer23 significantly contributed to CSF MHPG concentrations (p = .012). Higher concentrations of CSF MHPG were observed both in alcoholic violent offenders and population controls with HTR2C Ser23 genotype. Despite the association of Cys23Ser to CSF MHPG, HTR2C genotype was not associated with alcoholism, nor with other psychiatric disorders present in this sample.

CONCLUSIONS

We conclude that a functional HTR2C Cys23Ser polymorphism contributes to the interindividual genetic variation of CSF MHPG explaining 3% of the total variance. This finding suggests that 5-HT2C receptors are involved in the regulation of norepinephrine turnover in humans; however, HTR2C Cys23Ser does not appear to contribute to the risk of alcoholism, or its contribution to this complex and heterogenous disorder is too small to be detected by a sample of this size and structure.

CSF monoamine metabolite and beta endorphin levels in recently detoxified alcoholics and healthy controls: prediction of alcohol cue-induced craving?

BACKGROUND

Abnormalities in central neurotransmitter systems have been described in alcohol-dependent individuals and may contribute to alcohol craving. This study compared cerebrospinal fluid (CSF) levels of monoamine metabolites and beta endorphin levels in samples from early-onset alcohol-dependent patients (n = 20), late-onset alcohol-dependent patients (n = 14), and healthy controls (n = 23). It also evaluated whether these CSF measures levels predicted the degree of craving experienced in response to an alcohol cue.

METHODS

Individuals meeting DSM-III and -IV R-criteria for alcohol dependence, 1 to 3 months postdetoxification, and healthy controls underwent a lumbar puncture. Patients also completed a cue exposure test day between 3 and 15 days later.

RESULTS

Alcohol-dependent patients had lower CSF levels of the norepinephrine metabolite MHPG compared with the healthy subjects, but this difference disappeared when differences in age between the groups were accounted for. No other group comparisons between patients and healthy subjects reached significance. CSF levels of the dopamine metabolite HVA were significantly higher in the early-onset patients compared with the late-onset patients and controls. The CSF measures did not predict the precue levels of craving, or the increase in craving after alcohol cue exposure.

CONCLUSIONS

These results are inconclusive about the role of monoaminergic dysregulation in recovering alcoholics. They also question the utility of these CSF measures to predict alcohol cue reactivity in patients who have been sober at least 1 month.

[The neurobiology of depression]

Neurobiology dominates efforts to understand depression. This psychiatric illness is thought to result from dysfunctions in monoaminergic systems affecting norepinephrine, serotonin and dopamine. Abnormalities are linked to functional deficit of monoamines at several effector sites. Findings include reduced cerebrospinal fluid and urinary concentrations of metabolites, decreased plasma concentrations of precursors, modifications of receptor density and clinical effectiveness of drugs which increase neurotransmission in depressed patients. The original hypothesis of affective disorder envisaged a single transmitter model, but neuroscientific developments highlight the complexity of the central nervous system. Considerable evidence supports the hypothesis of combined alterations of monoaminergic functions and other systems like neuropeptides and neuroendocrine functions.

CSF monoamine metabolites in relation to the diagnostic interview for borderline patients (DIB)

The cerebrospinal fluid concentrations of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), 3-methoxy-4-hydroxyphenylglycol, and their ratios were studied in relation to the Diagnostic Interview for Borderline patients (DIB) evaluated retrospectively from hospital records for a sample of 202 patients participating in psychobiological programs on mood disorders. No correlations with the total DIB score were significant. Patients with borderline personality disorder (BPD) defined by a total DIB score of at least 7 or 6, respectively, did not differ significantly from non-BPD regarding the metabolites. However, for section II (impulse action pattern) of the DIB, those with an intermediate value of the section score had significantly higher levels of 5-HIAA and HVA, suggesting that such higher than normal concentrations may be protective against impulsive or suicidal behavior generated by an underlying psychiatric morbidity due to other risk factors.

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.

Decreased monoamine metabolites in frontotemporal dementia and Alzheimer's disease

The concentrations of the monoamine metabolites homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylglycol (HMPG) in the cerebrospinal fluid (CSF) of patients with clinical frontotemporal dementia (FTD; n = 30), early onset Alzheimer's disease (EAD; n = 33), late onset Alzheimer's disease (LAD, n = 27) and normal controls (n = 31) were determined using HPLC. ANCOVA showed no significant effect of neuroleptic medication, extrapyramidal signs, myoclonia or gender on the CSF levels of the monoamine metabolites. Homovanillic acid was significantly reduced in all diagnostic groups (FTD, p = 0.0002; EAD, p = 0.016; LAD, p = 0.013). 5-Hydroxyindoleacetic acid was significantly reduced in EAD (p = 0.013) and in LAD (p = 0.0014), and HMPG was reduced in LAD only (p = 0.020). HMPG was significantly higher in FTD compared to EAD (p = 0.0005) and LAD (p = 0.0003). CSF-5-HIAA was significantly reduced in patients with antidepressant medication (p = 0.006). ANCOVA within the FTD group showed no significant effect of neuroleptic or antidepressant medication, extrapyramidal signs, myoclonia, gender or FTD subtype on the CSF levels of the monoamine metabolites. The results suggest that CSF-HMPG might differentiate FTD from EAD and LAD, but not from normals.