Simultaneous determination of salsolinol enantiomers and dopamine in human plasma and cerebrospinal fluid by chemical derivatization coupled to chiral liquid chromatography/electrospray ionization-tandem mass spectrometry.

A sensitive, specific, and robust method to simultaneously determine enantiomeric salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, SAL), a potential biomarker implicated in alcohol-related neurotoxicity in a stereoselective manner, and its precursor dopamine (DA) has been developed using simple chemical derivatization and chiral separation coupled with electrospray ionization-tandem mass spectrometry (ESI-MS/MS). SAL enantiomers and DA were converted to stable pentafluorobenzyl (PFB) derivatives directly from aqueous media. Bulky PFB groups introduced into the SAL structure enabled baseline separation of SAL stereoisomers on a chiral column without cumbersome chiral derivatization to unstable SAL diastereomers. Subsequent analysis by ESI-MS/MS with multiple reaction monitoring (MRM) in the presence of deuterium-labeled internal standards allowed specific detection of both derivatives with a wide dynamic range (SAL, 0.5-5000 pg; DA, 0.02-20 ng). The limit of quantitation assayed in the plasma matrix was below 10 pg for each SAL enantiomer and 100 pg for DA. Both coefficient of variance and error for inter- and intraday measurements in the blank plasma were less than 10% for SAL and DA in the concentration range of 10-4000 pg/mL and 0.1-8 ng/mL, respectively. This strategy enabled routine and specific determination of both SAL enantiomers and DA from 0.5 mL of human plasma and cerebrospinal fluid, which has not been possible using existing methodologies.

Liquid chromatography with amperometric detection at a nano crystalline Ce-doped lead dioxide film modified electrode for determination of (R)-Salsolinol, (R)-N-methylsalsolinol and monoamine neurotransmitters in Parkinsonian patients' cerebrospinal fluid.

The fabrication and application of a novel electrochemical detector (ED) with nano crystalline Ce-doped lead dioxide film chemically modified electrode (CME) for liquid chromatography (LC) were described. The Ce-doped PbO(2) film was characterized by X-ray diffractometer (XRD) and scanning tunnel microscope (STM). The electrochemical behaviors of (R)-Salsolinol ((R)-Sal) at the CME were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was found that the CME exhibited an efficiently electrocatalytic effect on the current responses of (R)-Sal, (R)-N-methylsalsolinol ((R)-NMSal) and monoamine neurotransmitters. In LC-ED, all (R)-Sal, (R)-NMSal, dopamine (DA), norepinephrine (NE), 3-methoxy-4-hydroxyphenylglycol (MHPG), 3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) had good and stable current responses at the CME. The linear ranges of the nine analytes were over three orders of magnitude (R(2) > 0.995). The application of this method coupled with microdialysis sampling for the determination of (R)-Sal, (R)-NMSal and monoamine neurotransmitters in Parkinsonian patients' cerebrospinal fluid (CSF) was satisfactory.

Cerebrospinal fluid concentrations of atracurium, laudanosine and vecuronium following clinical subarachnoid hemorrhage.

BACKGROUND: Neuromuscular blocking agents may exert central nervous system effects when they reach the brain. This study assessed the concentrations and the time course of passage of vecuronium, atracurium, and its metabolite laudanosine in the cerebrospinal fluid (CSF) of patients undergoing intracranial aneurysm clipping. METHODS: Twenty-five patients with subarachnoid hemorrhage were randomly allocated to receive an intravenous infusion of vecuronium (n=13) or atracurium (n=12). Arterial blood and lumbar CSF were sampled before and 1, 2, 3, 4 and 8 h after the start of the relaxant infusion. The samples were analyzed by liquid chromatography-electrospray ionization mass spectrometry (vecuronium) and high-pressure liquid chromatography (atracurium and laudanosine). RESULTS: The data of 20 patients (10 in both groups) were analyzed. In 11 CSF samples from five patients atracurium was detected in concentrations from 10 to 50 ng/ml. Laudanosine was retrieved in all CSF samples at 1, 2, 3, 4 and 8 h; the highest CSF concentration of laudanosine occurred at 3 h [38 (18-63) ng/ml: median (range)]. Vecuronium was not found in any CSF sample. CONCLUSION: Significant concentrations of atracurium and laudanosine but not of vecuronium were detected in the CSF of patients during and immediately after intracranial aneurysm surgery.

Nasal administration of a physostigmine analogue (NXX-066) for Alzheimer's disease to rats.

The nasal route has been receiving attention for the administration of systemically active drugs because delivery is convenient, reliable and rapid. The aims of this study were to investigate the systemic absorption of nasally administered (3aS)-cis-1, 2, 3, 3a, 8, 8a-hexahydro-1, 3a, 8-trimethyl-pyrrolo-[2,3b]-indol-5-yl 3, 4 dihydro-2-isoquinolincarboxylate (NXX-066), a physostigmine analogue, in rats and to compare the uptake of the drug into the cerebrospinal fluid (CSF) after nasal and intravenous administration. NXX-066 (3 micromol/kg) was administered to both nostrils or into the vena jugularis of male Sprague-Dawley rats. Blood and CSF samples were obtained at regular intervals from the arteria carotis and by cisternal puncture, respectively. The concentrations of NXX-066 in the blood and CSF samples were measured using HPLC with fluorescence detection. NXX-066 was absorbed rapidly after nasal administration with the peak concentration occurring within 1.5 min. The nasal bioavailability of NXX-066 was 100+/-30% and the elimination from plasma was as rapid as that following intravenous administration. Low concentrations of NXX-066 were detected in the CSF after both intravenous and nasal administration. In conclusion, NXX-066 was rapidly and totally absorbed into the systemic circulation and uptake into the CSF was not enhanced by nasal administration in rats.

R- and S-salsolinol are not increased in cerebrospinal fluid of Parkinsonian patients.

Various investigators address an augmented synthesis of tetrahydroisoquinolines, such as salsolinol (SAL), or an increased N-methylation of these compounds as putative pathophysiologic mechanisms in Parkinson's disease (PD). Objectives of this study were (1) the evaluation of a putative elevation of enantiomers (R-, S-) of SAL and (2) the investigation of relations between these metabolic precursors of neurotoxic N-methylated-SAL (NMSAL) and dopamine in cerebrospinal fluid of untreated de-novo Parkinsonian patients and age- and sex-matched healthy controls. Levels of R- and S-SAL and dopamine did not significantly (R-SAL: P = 0.75, S-SAL: P = 0.69, dopamine: P = 0.46) differ and dopamine did not correlate to R-SAL and S-SAL in both groups. We conclude, that central accumulation of R-NMSAL, which is neurotoxic to dopaminergic nigrostriatal neurons, is not due to elevated synthesis of R-SAL and/or S-SAL in PD.

Increase in salsolinol level in the cerebrospinal fluid of parkinsonian patients is related to dementia: advantage of a new high-performance liquid chromatography methodology.

The study was carried out on the lumbar cerebrospinal fluid (CSF) samples taken from nonparkinsonian, early parkinsonian, and advanced parkinsonian patients. Some patients showed dementia, and some were treated with L-dopa. In the samples, salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline) was assayed with a newly developed sensitive high-performance liquid chromatography (HPLC) method; 3-O-methyldopa (3-O-MD) and homovanillic acid (HVA) were also assayed by HPLC. CSF salsolinol concentrations were significantly enhanced in patients with signs of dementia, regardless of the degree of parkinsonism, and were not affected by L-dopa treatment; HVA and, particularly, 3-O-MD levels were elevated in patients receiving L-dopa. The strong association of CSF salsolinol level with dementia, but not with L-dopa treatment suggests that salsolinol does not originate from L-dopa metabolism, and that its elevation is an indicator of neurodegenerative processes resulting in damage to brain areas mediating cognitive functions. We found no correlation between the advancement of parkinsonism and the concentrations of 3-O-MD and HVA.

[Salsolinol, 3-O-methyl-dopa and homovanillic acid in the cerebrospinal fluid of Parkinson patients]. / Salsolinol oraz 3-0-metyldopa i kwas homowanilinowy w plynie mózgowo-rdzeniowym u osób z choroba parkinsona.

Salsolinol is one of the dopamine-derived tetrahydroisoquinolines, supposed to be a potent dopaminergic neurotoxin, similar to MPTP. Its systemic administration induced parkinsonism in monkeys. The aim of the study was to compare the concentration of salsolinol and the metabolite of L-dopa, 3-O-MD, and the metabolite of dopamine, HVA, in the cerebrospinal fluid of patients with different degrees of parkinsonism, treated or nontreated with l-dopa. Lumbar CSF was obtained from 26 patients with Parkinson's disease (15 early and 11 advanced parkinsonism) and from six healthy controls. The presence of salsolinol, HVA and 3-O-MD was assayed with a sensitive HPLC method employing C18 (Hypersil BDS) column. The analysis of the results demonstrated that the concentration of salsolinol was related to the degree of parkinsonism but not affected by l-dopa treatment. In contrast, HVA and 3-O-MD were significantly elevated in patients receiving l-dopa but did not correlate with the severity of parkinsonism. The results suggest that salsolinol in the cerebrospinal fluid does not originate from exogenous l-dopa and its elevation in cerebrospinal fluid may be an indicator of the advancement of parkinsonism.

1-Benzyl-1,2,3,4-tetrahydroisoquinoline as a parkinsonism-inducing agent: a novel endogenous amine in mouse brain and parkinsonian CSF.

1-Benzyl-1,2,3,4-tetrahydroisoquinoline (1BnTIQ) was detected as a novel endogenous amine in mouse brain and parkinsonian CSF by using the gas chromatography-selected ion-monitoring method. The level of 1BnTIQ was very high in CSF of some parkinsonian patients compared with that of controls with other neurological diseases, the mean value being three times higher (parkinsonians: 1.17 +/- 0.35 ng/ml of CSF, n = 18; vs. controls: 0.40 +/- 0.10 ng/ml of CSF, n = 11; mean +/- SEM, not significantly different). The pole test, a toxicological examination to evaluate behavior abnormalities related to Parkinson's disease, was used to examine the pharmacological effect of 1BnTIQ in mice. Repeated administration of 1BnTIQ induced behavior abnormalities, which pretreatment with 1-methyl-1,2,3,4-tetrahydroisoquinoline could prevent. We suggest that 1BnTIQ may be related to the idiopathic Parkinson's disease.

Presence of N-methyl-norsalsolinol in the CSF: correlations with dopamine metabolites of patients with Parkinson's disease.

We could identify the MPTP-like compound and isoquinoline derivative N-methyl-norsalsolinol (2-MDTIQ) in cerebrospinal fluid (CSF) of patients with Parkinson's disease. The presence of 2-MDTIQ negatively correlated with the disease duration. In order to study the relationship between presence of 2-MDTIQ and dopamine metabolism, we examined 3-O-methyl-dopa (MDOPA) and homovanillic acid (HVA) levels in CSF of 15 normal control subjects and 34 patients with Parkinson's disease (PD). In the PD group in which 2-MDTIQ was detected, the HVA/MDOPA ratio was also negatively correlated with the duration of the disease and was increased when compared to patients without 2-MDTIQ. Since in both PD groups the daily L-dopa dose, the mean MDOPA levels, and the daily L-dopa dose/MDOPA ratio were nearly identical the results are not related to different L-dopa medications. In vitro experiments demonstrated 2-MDTIQ to inhibit monoamine oxidase activity in the caudate-putamen. These results suggest that 2-MDTIQ indicates an increased dopamine turnover in patients with PD. The enhanced metabolism at the beginning of the disease is not due to the presence of 2-MDTIQ since it inhibits dopamine metabolism. Thus, 2-MDTIQ, probably endogenously synthesized from dopamine, appears as a result of a compensatively activated dopaminergic system.

Presence of methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinolines, derivatives of the neurotoxin isoquinoline, in parkinsonian lumbar CSF.

The TIQ derivatives 2-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (2-MDTIQ) and 1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (1-MDTIQ, salsolinol) were identified the first time as possible endogenous neurotoxins in parkinsonian but not in normal human lumbar cerebrospinal fluid by high performance liquid chromatography with electrochemical detection. Additionally, MDTIQ analogues were incubated with a monoamine oxidase (MAO) assay. MAO was able to metabolize dose-dependently 2-MDTIQ, whereas 1-MDTIQ was not modified by the enzyme.

Interrelationship between activation of dopaminergic pathways and cerebrospinal fluid concentration of dopamine tetrahydroisoquinoline metabolite salsolinol in humans: preliminary findings.

The main objective of this study was to determine whether the activation of dopaminergic pathways, through adrenal-caudate transplantation, stimulated the production of dopamine and salsolinol in cerebrospinal fluid (CSF) of patients with Parkinson's disease. Dopamine sulfate and salsolinol sulfate in CSF specimens were measured by radioenzymatic technique. The results of this study demonstrated that the replacement of degenerative nigrostriatal neurons with new dopamine-producing cells by adrenal brain transplants in patients with Parkinson's disease resulted in significant increase (p less than 0.05) in CSF levels of free dopamine, dopamine sulfate, free salsolinol, and salsolinol sulfate as compared with preoperative levels. Moreover, the oral administration of L-dopa to these transplanted patients caused substantial (p less than 0.001) elevation in CSF levels of free dopamine (before L-dopa, 146 +/- 57 pg/ml; after L-dopa, 575 +/- 207 pg/ml), dopamine sulfate (before L-dopa, 1966 +/- 945 pg/ml; after L-dopa, 41679 +/- 29326 pg/ml), free salsolinol (before L-dopa, 43 +/- 29 pg/ml; after L-dopa, 186 +/- 90 pg/ml), and salsolinol sulfate (before L-dopa, 405 +/- 477 pg/ml; after L-dopa, 2908 +/- 2572 pg/ml), respectively.

Concentrations of atracurium and laudanosine in cerebrospinal fluid and plasma in three intensive care patients.

We have measured concentrations of atracurium and laudanosine in cerebrospinal fluid (CSF) and plasma in three intensive care patients receiving atracurium infusions of 22.5-106 h duration to maintain neuromuscular block. Two patients had suffered severe closed head injuries and the third patient had developed respiratory failure following the clipping of two intracranial aneurysms. The total dose of atracurium given was 14.3-136.6 mg kg-1; rate of infusion was 0.6-1.38 mg kg-1 h-1. Plasma concentrations of atracurium and laudanosine were 0.73-3.11 micrograms ml-1 and 0.48-8.65 micrograms ml-1, respectively; CSF concentration of laudanosine was 70-440 ng ml-1. No adverse effects attributable to these concentrations of laudanosine were observed.

Cerebrospinal fluid concentrations of laudanosine after administration of atracurium.

The concentration of laudanosine in cerebrospinal fluid (CSF) was measured in four patients undergoing brain electrode placement after the administration of atracurium. CSF: plasma laudanosine concentration ratios ranged from less than 1 to 14%, with a range of CSF laudanosine concentrations of less than 2-14 ng ml-1. One patient had no detectable laudanosine in CSF, but sampling in this patient was possible for only 30 min. There was no atracurium detectable in the CSF of any patient. We conclude that laudanosine crosses the blood-brain barrier and further study of its central nervous system effects in man is warranted.

Effect of adrenal-caudate transplantation on CSF levels of salsolinol sulfate in patients with Parkinson's disease.

The main objective of this study was to determine whether the activation of dopaminergic pathways through adrenal-caudate transplantation stimulates the production of the dopamine cyclic metabolite salsolinol in CSF of patients with Parkinson's disease. Salsolinol sulfate in CSF samples was assayed by radioenzymatic technique. The outcome of this study revealed that the replacement of degenerative nigrostriatal neurons with new dopamine-producing cells by adrenal brain transplants resulted in significant increase in CSF concentration of salsolinol sulfate as compared to preoperative levels.

Concentrations of atracurium and laudanosine in cerebrospinal fluid and plasma during intracranial surgery.

Concentrations of atracurium and laudanosine in cerebrospinal fluid (CSF) and plasma were assayed in nine patients receiving atracurium infusions of 111-251 min duration to maintain neuromuscular block during intracranial surgery. The total dose of atracurium was 1.57-2.60 mg kg-1 and the plasma concentration of atracurium was 1.27-5.44 micrograms ml-1. Concentrations of laudanosine in CSF and plasma increased during the infusion period, and after 125-140 min reached means of 202.5 ng ml-1 and 1448.7 ng ml-1, respectively. The highest recorded concentration of laudanosine in CSF was 570 ng ml-1, in one of two CSF samples found to contain atracurium. After operation, two patients had fits, but these were not thought to be related to laudanosine. It is concluded that during infusion of atracurium, laudanosine accumulates in both plasma and CSF.

Pharmacology of laudanosine in dogs.

The authors determined the pharmacokinetics (including transfer into cerebrospinal fluid [CSF]) and the cardiovascular and central nervous system (CNS) effects of laudanosine, a metabolite of atracurium. Eight dogs were anesthetized with halothane; blood pressure and a fronto-occipital electroencephalographic lead were monitored. Laudanosine (1 mg . kg-1 iv) was administered as a bolus, and its concentrations in plasma, CSF, urine, and bile were determined by liquid chromatography. Three-compartment modeling of plasma laudanosine concentrations yielded an elimination half-life for laudanosine of 113 +/- 24 min (mean +/- SD) and a clearance of 25 +/- 8 ml . kg-1 . min-1. CSF concentrations of laudanosine were highest 5-10 min after iv injection of laudanosine and ranged in concentration from 208 to 572 ng . ml-1 (i.e., 36-87% of the corresponding plasma concentrations). Unchanged laudanosine was found in urine (0.5-12% of injected dose) and bile (less than 0.1%); metabolites of laudanosine were found in both fluids. After a 6-h sampling period, dogs were hyperventilated with halothane (FIO2 = 0.2) to a PaCO2 of 26-28 mmHg. Laudanosine was then administered 2 mg . kg-1 iv every 5 min. With cumulative doses of 2-8 mg . kg-1, all dogs showed signs of "awakening" from anesthesia. Cumulative doses of 14-22 mg . kg-1 produced seizure activity in all animals. Mean arterial blood pressure decreased significantly to 86% of control levels at 1 min following administration of laudanosine (1 mg . kg-1 iv) and returned to control levels 4 min later.(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of acute ethanol on the catecholamine system in man as reflected in cerebrospinal fluid and urine. A new condensation product, 1-carboxysalsolinol.

Urine and cerebrospinal fluid (CSF) were collected from 10 healthy male volunteers after ingestion of 120 g ethanol and under similar conditions without ethanol. Dopamine (DA), homovanillic acid (HVA), norepinephrine (NE), 4-hydroxy-3-methoxyphenylglycol (HMPG), 4-hydroxy-3-methoxymandelic acid (HMMA = VMA), 1-carboxysalsolinol (1-CSAL), salsolinol (SAL) and methylated salsolinol (M-SAL) were analyzed with gas chromatography-mass spectrometry. In CSF collected 6 h after ethanol intake the concentration of NE and its metabolite HMPG were significantly elevated (P less than 0.025 and P less than 0.005, respectively) compared to control conditions. The other compounds analyzed did not change significantly. In urine collected during 10 h after ethanol administration the excretion of HMMA was significantly reduced (P less than 0.01) and the HMPG/HMMA ratio was significantly elevated (P less than 0.005) reflecting a change in the peripheral red-ox state during ethanol oxidation. The excretion of DA and its major metabolite HVA did not change. However, the DA-derived condensation products 1-CSAL (from DA and pyruvate) increased (P less than 0.001), while SAL (from DA and acetaldehyde) decreased (P less than 0.005) after ethanol ingestion compared to the control situation. The increased excretion of 1-CSAL indicated that the ethanol metabolism interferes with the glucose metabolism, probably through an acetaldehyde-mediated inhibition of the pyruvate dehydrogenase complex.

Catecholamines and metabolites in cerebrospinal fluid of teetotallers and sober alcoholics.

Dopamine (DA), homovanillic acid (HVA), salsolinol (SAL), methylated salsolinol (M-SAL), norepinephrine (NE) and 4-hydroxy-3-methoxyphenylglycol (HMPG) were measured in cerebrospinal fluid (CSF) from 8 alcoholics who had abstained from ethanol for 3 months and from 8 teetotallers. No significant differences in the concentrations of any of these catecholamines or their metabolites were found between the two groups. In the alcoholics there was a positive correlation between age and DA (P less than 0.005), NE (P less than 0.025) and SAL (P less than 0.005) and also between DA and SAL (P less than 0.01).