Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The striatum constitutes the most voluminous basal ganglia in man. It is issued from ganglionic eminences which are very early bound by limbic kernels. If the cortical and reticulo-spinal projections have been first described the existence of anatomical connexions with the limbic system offers a large number of functional possibilities. The knowledge of the distribution of the different chemical substances which are present within this structure as well as the enzymes necessary for their synthesis and destruction permits to establish a chemical mapping, the dopaminergic one being the best known. The dopaminergic synaptic function in the striatum helps to understand the respective roles of the pre and post-synaptic receptors as well as the mechanisms by which the other neuromediators can modulate the dopaminergic activity, the cyclic nucleotides being often necessary for this action. These fundamental data subtend the mechanism of action of most of the drugs which are involved in extrapyramidal phenomenons (neuroleptics, dopaminergic agonists) and allows to put forth physiopathological hypothesis on Parkinson disease, Huntington chorea, as well as certain induced or spontaneous dyskinetic states. The functions of the striatum are then evoked: if the role of this structure in motor control is critical, its involvement in complex behaviours is strongly suggested.
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PMID:[Neuropharmacological data on the striatum]. 3 37

Diphenylhydantoin (DPH) diminished the therapeutic effects of levodopa both in patients with parkinsonism and in patients with chronic manganese poisoning, as well as the levodopa-dependent dyskinesia for which the former were selected. In patients with Huntington chorea, it enhanced chorea and mental agitation and, thus, failed to conform with the postulated pharmacological reciprocity between Parkinson disease and Huntington chorea. These findings are in agreement with experiments done in animals in which DPH blocked a neuronal response to dopamine.
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PMID:Diphenylhydantoin. Blocking of levodopa effects. 12 56

Comparison of the properties of blood platelets and serotonergic synaptosomes suggests that the human platelet can serve as an appropriate model for the transport, metabolism, and release of serotonin (5-HT) by CNS serotonergic neurons. The study of blood 5-HT levels and platelet 5-HT pharmacodynamics in patients with a variety of psychiatric and neurologic disorders has generated interesting leads into possible abnormalities of CNS 5-HT neurons in these patients. This article reviews the experimental evidence, which uses the human platelet model to investigate neurotransmitter-related abnormalities in Down syndrome, mental retardation, infantile autism, hyperactivity syndromes (minimal brain dysfunction), schizophrenia, affective disorders, Duchenne muscular dystrophy, Parkinson disease, Huntington chorea, and migraine headaches.
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PMID:The human platelet. A diagnostic and research tool for the study of biogenic amines in psychiatric and neurologic disorders. 14 Jun 32

The habituation index is a quantitative expression of the ability of the orbicularis oculi (blink reflex) to adapt to a series of electrical stimuli applied to the supraorbital region. This parameter has been studied in a group of normal control subjects, and the results compared with those in cases of idiopathic and drug-induced Parkinsonism, states of dementia, and dyskinesias such as Huntington's chorea and senile chorea. Patients with Huntington's chorea showed a tendency for the reflex to habituate readily in contrast to patients with dementia caused by cortical atrophy and those with Parkinson's disease. Younger patients with Huntington's chorea had indices within the normal range. It seems unlikely that this test will prove of value in the detection of clinically unaffected relatives. Where dementia was associated with a reversible intracranial lesion, the habituation index was studied before and after treatment. Failure of habituation in this condition appears to be due to the release of a primitive protective reflex.
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PMID:Habituation of the orbicularis oculi reflex in dementia and dyskinetic states. 15 Nov 27

Huntington's chorea is a dominantly inherited disorder that usually leads to involuntary movements in the third or fourth decade. On gross pathological examination of the post-mortem brain there is a marked atrophy of the caudate nucleus and putamen. Histological examination reveals cell loss in most regions of the brain, although the hippocampus is usually remarkably free of any abnormalities. Studies to detect a biochemical defect in patients with chorea have been largely unrewarding. Since chorea appears to be the clinical counterpart of Parkinson's disease a number of investigations on dopamine metabolism have been carried out by measuring dopamine in the post-mortem choreic brain, and HVA, a metabolite of dopamine, in the CSF of patients. Most studies have found the dopamine concentrations to be normal or sometimes decreased and the activity of the biosynthetic enzyme for dopamine, tyrosine hydroxylase, is normal. The discovery that the inhibitory neurotransmitter, GABA, and the biosynthetic enzyme GAD are greatly decreased in the post-mortem choreic brain provides some rational explanation for the uncontrolled movements in this disorder. The other significant abnormality found in many, but not all, choreic post-mortem brains has been a decrease in the biosynthetic enzyme for acetylcholine, choline acetyl transferase. The evidence that GABA receptors are intact in choreic brain provides an added stimulus for the development of useful GABA-mimetic drugs. For the ultimate eradication of this distressing disorder, however, a search must continue for the primary defect in order that this can be detected before the onset of symptoms, or hopefully in amniotic fluid.
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PMID:Neurochemical findings in Huntington's chorea. 15 97

A univocal disorder of dopaminergic activity in the nerve structures responsible for extra-pyramidal motility does not take into account the total phenomena seen in psychomotor neurological studies. The hypothesis of two categories of dopaminergic receptors-respectively excitatory (DA) and inhibitory (DAi)--in the striatal and mesolimbic structures concerned, was derived from experimental and clinical anatomical cytological, and pharmacological data. This duality of the receptors could establish a relationship between dopaminergic mediating, mechanism and adrenergic mediation for with the existence of a least two types of distinct receptors, alpha and beta, has been demonstrated. The author discusses the physiopathology of neuromotor disorders wuch as Parkinson's disease, chorea, and various types of dyskinesias, in relation to this dual mediation. By separation of dopamine antagonists and agonists in this new context, it should be possible to have a more selective approach, which would be better adapted, therefore, for the treatment of these affections. The study of the effects of a new medication, tiapride, on dyskinesias provoked by levodopa in parkinsonian patients, is a step forwards in this new method exploration in neurology.
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PMID:[Duality of dopaminergic receptors. Pharmacologic and clinical perspectives]. 21 3

Oxiperomide, a new dopamine-receptor antagonist, was found to decrease dyskinesias in patients with Parkinson's disease receiving levodopa or other dopamine agonists without necessarily increasing Parkinsonian symptoms. Oxiperomide also decreased spontaneous dyskinesias in those with tics and chorea and to a less extent in those with torsion dystonia, without necessarily causing Parkinsonism. These results provide evidence that more than one population of dopamine receptors exist in the extra pyramidal system, and encourage the search for selective dopamine antagonists.
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PMID:Effect of new dopamine-blocking agent (oxiperomide) on drug-induced dyskinesias in Parkinson's disease and spontaneous dyskinesias. 63 46

Levodopa-induced dyskinesias (LID) in Parkinson's disease (PD) may be classified into three main categories: "On" dyskinesias, diphasic dyskinesias (DD), and "off" periods. The study of 168 parkinsonian patients showed that about half (n = 84) showed one pattern of LID only. A combination of two was present in 68, and 16 had the three presentation patterns. A fairly good correlation between type of dyskinesia and presentation pattern was established. Chorea, myoclonus, and dystonic movements occurred during the "on" period. Dystonic postures, particularly affecting the feet, were mainly present in the "off" period, but a few patients had a diphasic presentation. Repetitive stereotyped movements of the lower limbs always corresponded to DD. Acute pharmacological tests using dopamine agonists (subcutaneous apomorphine 3-8 mg; intravenous lisuride 0.1-0.15 mg) and dopamine antagonists (intravenous sulpiride 200-400 mg and intravenous chlorpromazine 25 mg) were performed in 40 patients. Dopamine agonists enhanced "on" dyskinesias and markedly reduced or abolished "off" period dystonia and DD. Dopamine antagonists reduced all types of LID but usually aggravated parkinsonism. These clinical and pharmacological results indicate that LID in PD are a heterogeneous phenomenon difficult to explain on the basis of a single pathophysiological mechanism.
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PMID:Levodopa-induced dyskinesias in Parkinson's disease: clinical and pharmacological classification. 135 58

Over the past 3 years, there has been great interest in transplantation therapy in the treatment of Parkinson's disease. Following the impressive results reported by Madrazo in the spring of 1987, more than 350 cases of adrenal medullary implantation have been performed worldwide. There has been a significant reduction in "off" time and an increase in "on" time without chorea in 40% of patients having this procedure. The duration of effect is 1 year in half of these cases, with the other half (20% of all patients) still demonstrating significant improvement 3 years after the procedure. The mechanism of the bilateral beneficial improvement is unknown. The survival of adrenal medullary tissue has not been demonstrated at autopsy. It is thought that the mechanism of improvement involves either regenerative sprouting of the remaining dopamine producing neurons as a consequence of the release of neurotrophic factors or an interruption of the striatal pallidal output inhibitory influence of the basal ganglia on the thalamus (or both). Fetal mesencephalic implantation has also been attempted in more than 100 cases worldwide. The improvements when seen are not any more dramatic than those following the best results of adrenal medullary implantation. Graft survival has not been proved; it remains a possibility that interruption of the putamino-subthalamic pallidal pathway or a trophic influence of the tissue provides an alleviation in parkinsonism. The ethical controversy, need for long-term immunosuppression, and difficulty with obtaining tissue of the appropriate age and delivering the appropriate quantity to the putamen have made this technique less than adequate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Transplantation in the treatment of paralysis agitans (Parkinson's disease). 145 72

Dyskinesias associated with dopaminergic treatment in idiopathic Parkinson's disease (PD) can be indistinguishable from those arising spontaneously in other conditions involving degeneration of, or damage to, the basal ganglia. However, those due to levodopa treatment of PD disappear on cessation of therapy. We report a patient with a clinical diagnosis of PD who, on levodopa treatment, developed hemiballism and chorea that were originally thought to be drug induced. However, the dyskinesias persisted despite stopping levodopa. Postmortem analysis showed a multisystem degeneration.
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PMID:Hemiballism and chorea in a patient with parkinsonism due to a multisystem degeneration. 841


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