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PubMed1996

[Keratitis and corneal edema associated with levodopa use--a case report].

We report a patient who developed keratitis and corneal edema during treatment with carbidopa-levodopa. The patient was a 34-year-old woman who complained of apraxic gait after anoxic brain damage caused by ventricular arrhythmia. She had difficulty in walking. While doses of droxidopa, flecainide acetate and amantadine HCl were kept at the same levels as before several weeks, administration of carbidopa-levodopa was gradually increased from an initial dose of 100 mg per day to 300 mg per day over a period of 10 days in an attempt to relieve her apraxic gait. Ten days after initiation of treatment with carbidopa-levodopa, her postural instability and unsteady gait slightly improved. However, after 8 days of treatment with carbidopa-levodopa, she complained of blurred vision. Ophthalmologic examination showed keratitis (corneal endothelitis) and corneal edema. After stopping carbidopa-levodopa, the keratitis dramatically improved. Cessation of the drug therapy resulted in a return of vision to normal levels by the 7th day. Although there had been no previous reports of corneal lesion caused by levodopa, we suspected that keratitis and corneal edema were associated with carbidopa-levodopa use, especially in combination treatment with flecainide acetate, and amantadine HCl. The process was reversible and presumably could have been prevented by a shorter term of medication.

Adult↗
PubMed1993

Primary progressive freezing gait.

Freezing gait is an incapacitating symptom often observed in patients with Parkinson's disease. It has been less frequently described in association with multi-infarct state, multisystem atrophies, and normotensive hydrocephalus. In our movement disorder clinic, we have diagnosed (and followed up to 3 years; median, 16 months), 18 patients in whom progressive freezing gait was the sole neurological dysfunction. These 15 men and 3 women (aged 60-82 years; 74 +/- 6) were subjected to an extensive neurological workup that included clinical evaluation, videotaping for grading of gait disability, comprehensive blood and cerebrospinal fluid (CSF) analysis, and brain computed tomography (CT) and magnetic resonance imaging (MRI). Mean disease duration was 2.5 +/- 1.9 years (range, 0.5-6). Neurological examination disclosed freezing gait, often associated with varying degrees of postural instability. The degree of freezing gait ranged from sudden motor blocks only when confronted with obstacles to severe disability with total inability to start walking requiring a walker, massive assistance, or a wheelchair. However, patients could mimic gait movements with absolutely no freezing when seated or lying prone, and most of them could overcome arrests by the "walking-over-lines" maneuver. Otherwise, neurological examination was normal with no signs of bradykinesia, rigidity, or tremor. Blood chemistry and CSF analysis were normal. Brain CT and MRI were normal or showed mild cortical atrophy in 12 and putative lacunes in 6 patients. Therapy with levodopa or dopamine agonists was ineffective. During the follow-up period, a gradual progression of the freezing gait was observed. However, it remained unaccompanied by any other neurological findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed2006

The discovery of the pressor effect of DOPS and its blunting by decarboxylase inhibitors.

In the 1950s it was found that an artificial aminoacid, 3,4-threo-dihydroxyphenylserine (DOPS), was converted to norepinephrine (NE) in a single step by the enzyme L-aromatic amino acid decarboxylase (AADC), bypassing the need for the rate limiting enzyme dopamine beta hydroxylase. Trying to replicate the success of dihydroxyphenylalanine (DOPA) in the treatment of Parkinson disease, treatment with DOPS was attempted in patients with autonomic failure who have impaired NE release. DOPS improved orthostatic hypotension in patients with familial amyloid polyneuropathy, congenital deficiency of dopamine beta hydroxylase, pure autonomic failure and multiple system atrophy. DOPS pressor effect is due to its conversion to NE outside the central nervous system because concomitant administration of carbidopa, an inhibitor of AADC that does not cross the blood-brain barrier, blunted both the increase in plasma NE and the pressor response. DOPS pressor response is not dependent on intact sympathetic terminals because its conversion to NE also occurs in non-neuronal tissues.

Animals↗
PubMed1988

Effect of monoamine precursors on the forced-swimming test in mice.

The antidepressant properties of monoamine precursors were evaluated by the forced-swimming test for mice developed by Porsolt et al. DOPA but not 5-hydroxytryptophan (5HTP) shortened immobility at doses that did not increase locomotor activity. Although L-threo-dihydroxyphenylserine (DOPS), an artificial norepinephrine (NE) precursor, did not change immobility in intact mice, DOPS significantly reduced immobility in mice pretreated with the selective NE neurotoxin DSP4. These results suggest possible antidepressant properties of DOPA and DOPS, the latter of which may act as an antidepressant in a certain NE-depleting condition.

5-Hydroxytryptophan↗
PubMed1988

Memory effect of DL-threo-3,4-dihydroxyphenylserine (DOPS) in human Korsakoff's disease.

A group of amnesic patients with Korsakoff's disease were treated with a single 1 g dose of DL-threo-3,4-dihydroxyphenylserine (DOPS) and placebo (lactose) in a double-blind crossover study. Three hours following administration, patients were given a battery of psychometric tests to determine the effects of the treatment on memory functions. Administration of DOPS had a significant effect on performance on the Memory Passages test but not on any of the other measures of memory. The effect of DOPS on Memory Passages is similar to the response observed following administration of clonidine in Korsakoff patients. Blood pressure and pulse, measured before and every 2 h after treatment, were unaffected by DOPS.

Alcohol Amnestic Disorder↗
PubMed1980

Effect of increased pancreatic islet norepinephrine, dopamine and serotonin concentration on insulin secretion in the golden hamster.

The purpose of this study was to determine if increased concentrations of pancreatic islet norepinephrine, dopamine, or serotonin after insulin secretion. Golden hamsters received intraperitoneal injections of the norepinephrine precursor DL-threo-dihydroxyphenylserine, the dopamine precursor L-3,4-dihydroxyphenylalanine, or the serotonin precursor 5-hydroxytryptophan with and without pretreatment of the hamsters with the monoamine oxidase inhibitor tranylcypromine. Administration of the monoamine precursors to animals pretreated with tranylcypromine resulted in a mean increase in plasma glucose of 192% and a mean decrease in plasma insulin of 58%. Using a collagenase isolation technique, islets from control and treated animals were evaluated for monoamine content and insulin secretory capacity. The monoamine concentrations in control islets, in mumol/kg wet weight, were: norepinephrine 42 +/- 8; dopamine 8 +/- 2; and serotonin 26 +/- 9. Administration of the appropriate precursor to control hamsters resulted in a 1.9-fold (norepinephrine), 6-fold (dopamine), and 22-fold (serotonin) increase in monoamines. There was no alteration in the glucose (16.3 mmol/l)-stimulated in vitro insulin secretion from islets obtained from these hamsters. Administration of the precursors to hamsters pretreated with tranylcypromine resulted in a 3.5-fold (norepinephrine), 22-fold (dopamine), and 59-fold (serotonin) increase in monoamines. Glucose-stimulated in vitro insulin secretion from islets obtained from these hamstes was completely blocked. This study suggest that high concentrations of norepinephrine, dopamine, and serotonin in the pancreatic islets can decrease glucose-stimulated insulin secretion.

5-Hydroxytryptophan↗
PubMed1990

Acute autonomic and sensory neuropathy: a case report.

A female patient with acute autonomic and sensory neuropathy is described. Urinary disturbance developed rapidly and was followed by orthostatic syncope, absence of lacrimation, salivation and sweating, and sensory impairment. Muscle strength had been consistently normal despite diffuse muscular atrophy. Marked decrease in the number of small myelinated and unmyelinated fibres was revealed in biopsied sural nerve. Eighteen months after the onset, her autonomic symptoms have partially improved.

Acute Disease↗
PubMed1975

[Formation of norapinephrine in the rat brain after administration of ((+)-erythro-3,4-dihydroxyphenylserine(author's transl)].

Fluorescence microscopy of rat brains after administration of (+)-erythro-DOPS has been studied. (+)-erythro-DOPS induced an increase of brain NE part of which was formed in the capillary walls. The slight diminution of this increase when (+)-erythro-DOPS was administered after inhibition of peripheral decarboxylase, might result from the algebraic sum of two inversely acting processes: suppression of NE synthesis in the capillary walls and enhancement of parenchymatous NE in some brain areas. (+)-erythro-DOPS enters different brain structures non specifically and NE is formed in DA and 5-HT systems, displacing the amines especially at the terminals; the NE formed by (+)-erythro-DOPS in NE systems should be rapidly catabolised. Possible pharmacological effects of (+)-erythro-DOPS administration involve consideration of the lack of topical specificity of NE formation; the displacement of 5-HT and DA; and the fact (+)-erythro-DOPS produces (+)-NE, and not naturally occurring NE.

Animals↗
PubMed1986

Reversal of the reserpine-induced ptosis by L-threo-3,4-dihydroxy-phenylserine (L-threo-DOPS), a (-)-norepinephrine precursor, and its potentiation by imipramine or nialamide.

The effect of L-threo-DOPS on the reserpine-induced ptosis in mice and its modification by imipramine, a norepinephrine (NE) uptake inhibitor, or nialamide, a monoamineoxidase inhibitor, were studied. Intraperitoneal (i.p.) injection of L-threo-DOPS (800 mg/kg) significantly reduced the severity of the ptosis. This reversal of the ptosis by L-threo-DOPS was markedly potentiated by i.p. injection of either imipramine (2.5 mg/kg) or nialamide (30 mg/kg). Response to L-threo-DOPS was also significantly potentiated by intracerebroventricular (i.c.v.) injection of imipramine (10 micrograms). On the other hand, this treatment with imipramine (10 micrograms, i.c.v.) also significantly potentiated the reversal of the ptosis by NE (20 micrograms, i.c.v.), but the reversal by the subcutaneous (s.c.) injection of NE (1 and 3 mg/kg) was not affected. Reserpine (5 mg/kg, i.p.) markedly decreased the brain content of NE in mice, whereas L-threo-DOPS (400 mg/kg, i.p.) slightly restored it. Moreover, by the pretreatment with nialamide (30 mg/kg, i.p.), L-threo-DOPS produced a significant increase in the brain content of NE in reserpine-treated mice. These results suggested that L-threo-DOPS was capable of reversing the reserpine-induced ptosis due to the formation, at least in part of (-)-NE at the synaptic sites of central noradrenergic neurons.

Animals↗
PubMed1980

Effect of infused L-threo-3,4-dihydroxyphenylserine on adrenergic activity in patients with familial amyloid polyneuropathy.

L-threo-3,4-dihydroxyphenylserine (DOPS), an immediate precursor amino acid of (-)-norepinephrine, was used as a pharmacological tool to investigate the pathophysiology of the peripheral sympathetic nervous system in Type 1 familial amyloid polyneuropathy. Patients with the well-established disorder showed an enhanced pressor response to L-threo-DOPS under conditions that produced no change in normal subjects. While octopamine induced a brisk pressor response, L-threo-DOPS produced a slow and prolonged change in blood pressure, with a marked concomitant increase in urinary excretion of norepinephrine. A slight increase in urinary excretion of total metanephrine was observed in both groups, but there was no significant increase in serum dopamine-beta-hydroxylase activity. Since infusion of dilute norepinephrine into patients also produced a markedly hypersensitive response, the characteristic pressor response to L-threo-DOPS was indicative of denervation supersensitivity of adrenergic receptors to norepinephrine formed enzymatically from L-threo-DOPS.

Adult↗
PubMed1982

Pharmacokinetic studies of oral L-threo-3,4-dihydroxyphenylserine in normal subjects and patients with familial amyloid polyneuropathy.

The pharmacokinetics of oral L-threo-3,4-dihydroxyphenylserine (L-threo-DOPS) was studied in 7 normal subjects and 7 patients with familial amyloid polyneuropathy. Each person swallowed a single 300 mg dose in the fasting state, and L-threo-DOPS in plasma and urine was determined by high performance liquid chromatography with an electrochemical detector after separation on a boric acid gel column. L-threo-DOPS was slowly absorbed by normal subjects; the maximum plasma concentration occurred 3 h after administration and 20% of the oral dose was recovered unchanged in the urine within 12 h. It induced a substantial elevation of plasma norepinephrine levels, the peak being attained at 5 h, but without any change in blood pressure. In the patients, the absorption and metabolism of L-threo-DOPS were delayed, and a prolonged pressor response was observed, with a peak after 8 h. It was concluded that the effects on plasma norepinephrine and blood pressure of oral L-threo-DOPS were essentially equal to those of twice as large a dose of DL-threo-DOPS.

Adult↗
PubMed1985

DL-threo-DOPS as a precursor of noradrenaline.

DL-threo-Dihydroxyphenylserine (DL-threo-DOPS) is a non-physiological precursor of noradrenaline (NA). The formation of NA from DL-threo-DOPS has been reported to occur in various mammalian tissue. Since NA deficiency is thought to be underlying mechanism in several neurological disorders, we studied the role of the DL-threo-DOPS as a precursor of NA. In rats treated with DL-threo-DOPS, heart NA levels increased in a dose-dependent manner with maximal effect obtained 1 h after intraperitoneal injection of the drug. However, no effect of DL-threo-DOPS on brain NA levels or DA metabolism was detected. The effect of DL-threo-DOPS on heart NA levels was completely inhibited in the presence of carbidopa and significantly enhanced in the presence of pargyline. Under these conditions, DL-threo-DOPS had no effect on brain catecholamines. Depletion of catecholamines was obtained by pretreatment with either alpha-methyl-p-tyrosine (AMPT), reserpine or FLA-63. DL-threo-DOPS increased NA levels in the heart but not in the brain. Finally, coadministration of DL-threo-DOPS with levodopa potentiated the effect of levodopa on brain DA metabolism. This effect was independent of peripheral dopa decarboxylase activity and was also shown in circling behaviour in rats with unilateral destruction of the nigrostriatal pathway. In rats, DL-threo-DOPS is an effective peripheral precursor of NA but the drug itself has no effect on brain catecholamines. DL-threo-DOPS may, however, enhance levodopa effects in the brain.

Animals↗
PubMed1990

High-performance liquid chromatographic analysis of monoamines and some of their gamma-glutamyl conjugates produced by the brain and other tissues of Helix aspersa (Gastropoda).

1. Earlier reports from this and other laboratories have indicated that wide variations exist in estimates of the concentrations of norepinephrine in the brain and heart of the snail Helix aspersa. This is a report on investigations of norepinephrine concentrations in Helix aspersa tissues using high-performance liquid chromatography with electrochemical detection. In addition, the effects of treatment with some amino acid precursors or enzyme inhibitors on the concentrations of norepinephrine, dopamine, 5-hydroxytryptamine, and some of their metabolites were investigated. 2. The levels of norepinephrine in the brain were low (46 ng/g) in comparison to dopamine (2.1) micrograms/g) and 5-hydroxytryptamine (2.6 micrograms/g). Epinephrine was not observed in either snail heart of snail nervous tissue. 3. Administration of L-3,4-dihydroxyphenylalanine resulted in elevated snail brain dopamine, while 3,4-dihydroxyphenylserine treatment increased norepinephrine. Treatment with blockers of tyrosine hydroxylase and aromatic-L-amino acid decarboxylase reduced dopamine concentrations without affecting 5-hydroxytryptamine. 4. The dopamine metabolite 3,4-dihydroxyphenylacetic acid was observed only after administration of L-3,4-dihydroxyphenylalanine or dopamine and then only in very small amounts. At no time was the dopamine metabolite homovanillic acid or the 5-hydroxytryptamine metabolite 5-hydroxyindoleacetic acid observed in brain, heart, or whole-body extracts of the snail. 5. Incubation of nervous tissue with either dopamine or 5-hydroxytryptamine resulted in the production of electrochemically active metabolites which were identified by oxidation characteristics and cochromatography with synthesized standards as the gamma-glutamyl conjugates of the amines. Treatment of snails with 5-hydroxytryptamine or dopamine also resulted in the production of gamma-glutamyl conjugates. 6. The present experiments show that great care must be exercised when measuring monoamines and their metabolites in gastropod tissues by high-performance liquid chromatography with electrochemical detection.

Animals↗
PubMed1987

Uptake of L-threo-dihydroxyphenylserine into human brain synaptosomes.

Out of four diastereoisomers of 3,4-dihydroxyphenylserine (DOPS), L-threo- and L-erythro-isomer were found to be taken up into human brain synaptosomes. The uptake of L-threo-DOPS was dependent on the temperature and sensitive to the metabolic inhibitors. The L-threo-DOPS uptake proved to be saturable and carrier-mediated transport with two different kinetic characteristics; a high-affinity and low-capacity and a low-affinity and high-capacity system. The apparent Km values of these two systems were obtained to be 28.6 microM and 2.47 mM, respectively. The high-affinity transport was inhibited by glycine, L-tyrosine, L-proline, L-serine, L-Dopa, L-tryptophan, and L-phenylalanine. The inhibition by L-tyrosine was competitive in regard to L-threo-DOPS. The L-threo-DOPS uptake was inhibited by 2,4-dinitrophenol, sodium cyanide and other uncouplers of oxidative phosphorylation and by ouabain, an inhibitor of Na+, K+-ATPase, indicating that the uptake is coupled to ATP hydrolysis. On the other hand, L-threo-DOPS uptake by the low-affinity system was not inhibited by metabolic inhibitors, indicating that it may be facilitated diffusion common to high concentrations of L-amino acids.

Amino Acids↗
PubMed1983

DL-3,4-threo-DOPS in Parkinson's disease: effects on orthostatic hypotension and dizziness.

Parkinsonian patients with orthostatic hypotension and dizziness due to usual antiparkinson therapy have been treated with the precursor amino-acid of noradrenaline, DL-3,4-threo-dihydroxyphenylserine (DL-3,4-threo-DOPS). Oral and intravenous administration improved these side effects significantly. A combined treatment of L-dopa, peripheral decarboxylase inhibitor and DL-3,4-threo-DOPS seems to be of benefit with respect to akinesia and orthostatic hypotension.

Aged↗