Syndromes simulating myasthenia gravis.
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Adult↗
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Results for “EXTRAPYRAMIDAL TRACTS”
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Dopamine in the extrapyramidal motor function. A study based upon the MPTP-induced primate model of parkinsonism.
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1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
Anticholinergic activity of antipsychotic drugs in relation to their extrapyramidal effects.
Antipsychotic drugs were evaluated with two indices of anticholinergic activity, mydriasis in mice in vivo and antagonism of carbamylcholine-induced contractions of guinea-pig tracheal strips in vitro. The drugs from most to least potent as oral mydriatic agents were mepazine, clozapine, thioridazine, promazine and chlorpromazine. Trifluoperazine, pimozide and haloperidol were inactive. These results were consistent with the hypothesis that anticholinergic activity of antipsychotic drugs is inversely related to their propensity to produce extrapyramidal effects in man. In vitro results appeared to predict the incidence of extraphyramidal effects less accurately than in vivo results.
Animals↗
Differential effect of neuroleptic drugs on dopamine turnover in the extrapyramidal and limbic system.
In gallamine-immobilized cats, the caudate nucleus and the nucleus accumbens septi were perfused by means of a push-pull cannula and dopamine was measured in the perfusate. Chlorpromazine (10 mg kg(-1)) and clozapine (20 mg kg(-1)), administered intravenously, enhanced the release of dopamine. The effect of chlorpromazine was similar in both regions whereas that of clozapine was more pronounced in the nucleus accumbens than in the caudate nucleus. Furthermore, in the rat, sulpiride, clozapine and thioridazine increased the homovanillic acid concentration in striatum and limbic system to a similar extent. However, following probenecid administration, the net effect of these drugs on homovanillic acid accumulation was more marked in the limbic system than in the striatum whereas haolperidol and chlorpromazine had a similar effect in the two regions. It is concluded that, in contrast to haloperidol and chlorpromazine, sulpiride, clozapine and thioridazine may preferentially affect the limbic dopaminergic transmission. This possibly accounts for the fact that sulpiride, clozapine and thioridazine display an antipsychotic action and yet cause less extrapyramidal side effects than haloperidol and chlorpromazine.
Animals↗
Involvement of mesolimbic and extrapyramidal nuclei in the motor depressant action of narcotic drugs.
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Animals↗
Cortical and long spinal actions on lumbosacral motoneurones in the cat.
1. The effects of stimulating forelimb afferents on various ipsilateral motoneurones of the hind limb have been compared with those of volleys set up in the contralateral pericruciate cortex in cats anaesthetized with chloralose. 2. With intact neuraxis, brachial plexus volleys evoke discharge of flexor and extensor motoneurones; short cortical tetani also elicit discharge mainly of flexor motoneurons. After a pyramid-sparing brainstem lesion, little or no firing is evoked by either input. 3. Monosynaptic reflex testing and intracellular recording reveal subthreshold actions on hind-limb motoneurones, inhibition of FDHL and later facilitation of extensors and flexors by forelimb volleys, facilitation of flexors and extensors together with inconstant inhibition of the latter, by cortical stimulation. 4. Interruption of medullary extrapyramidal paths greatly reduces intensity and duration of facilitation from the forelimb, and largely removes cortically evoked extensor facilitation. Inhibition of FDHL from forelimb and cortex is unchanged; cortical volleys continue to facilitate flexors, and have mainly inhibitory action on extensors in these 'pyramidal' preparations. 5. Hyperpolarization of FDHL motoneurones occurs in response to forelimb and cortical volleys, of time course corresponding to depression of test reflexes. Spinal pathways responsible for the two inhibitory actions are independent, and unless each is very strong, their separate actions summate when elicited together. 6. Receptive field for FDHL inhibition from the forelimb is located distally in the forepaw, and its receptors are largely served by cutaneous fibres of low threshold; some Group II fibres in distal muscle nerves also contribute. Receptive field for facilitation embraces the whole limb, and the executant afferent fibres are of higher threshold. 7. Natural stimulation of the forelimb can evoke the long spinal actions, vibration or light pressure on the forepaw eliciting FDHL inhibition, and strong pinching evoking the more general facilitation. Possible functional roles of these actions in the intact animal are discussed.
Animals↗
A direct role of dopamine in the rat subthalamic nucleus and an adjacent intrapeduncular area.
The subthalamic nucleus, a clinically important component of the extrapyramidal motor system, and a lateral area extending into the peduncle contain catecholamine terminals and dopamine receptors coupled to adenylate cyclase. In addition, dopamine agonists administered in vivo enhance glucose utilization in the region. Thus, neuronal function in this region is directly affected by dopamine and dopaminergic drugs.
Adenylyl Cyclases↗
Tetrabenazine for extra-pyramidal movement disorders.
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Extrapyramidal Tracts↗
Effect of tetrabenazine on extrapyramidal movement disorders.
Thirty patients with various extrapyramidal movement disorders were treated for prolonged periods with 75 to 225 mg. daily of tetrabenazine. In patients with choreiform and hemiballistic motor activity the involuntary movements were diminished or abolished. In patients with cerebellar or Parkinsonian tremor the tremor was aggravated in moderately severe cases, but was uninfluenced in severe cases. In all cases the dyskinesia returned when- the drug was stopped.Side-effects were inconsiderable and disappeared on reducing the dose slightly. Hence the drug may be an important alternative to neurosurgical treatment of hyperkinesias and especially suitable for severely disabled patients.
Chorea↗
Drug intoxication and neurological episodes in chronic renal failure.
Of 178 episodes of neurological derangement in 103 patients with renal failure, only about 40% were due to known causes such as hypertension or electrolyte failure. One-third were due to drug intoxication and no definite aetiology was found for the remainder. Drug intoxication is due partly to the accumulation of a drug normally excreted by the kidney and partly to a greater susceptibility of the central nervous system in uraemic patients. The prognosis is favourable.
Cerebrovascular Disorders↗
Early pathological changes in the parkinsonian brain demonstrated by diffusion tensor MRI.
OBJECTIVE: To determine whether the fractional anisotropy (FA) of magnetic resonance diffusion tensor imaging is decreased in the nigrostriatal projection in parkinsonian patients. METHODS: FA values were compared in the extrapyramidal system of 12 patients with Parkinson's disease and eight age matched normal controls. RESULTS: Patients with Parkinson's disease had significantly decreased FA in the region of interest along a line between the substantia nigra and the lower part of the putamen/caudate complex, in which most of the nigrostriatal dopaminergic neurones are included. Loss of FA in this region was obvious even during the early clinical stages of Parkinson's disease. CONCLUSIONS: Assuming that the loss of FA parallels the neuronal change in the brain, the results are consistent with the view that more than half the dopaminergic neurones in the nigrostriatal projection are lost before the onset of Parkinson's disease. Close comparison of FA in the basal ganglia may contribute to the early diagnosis of Parkinson's disease.
Aged↗
Huntington's chorea and tryptophan.
Daily use of 7 g l-tryptophan and 70 mg pyridoxine for 14 days led to no deterioration of objectively measured manual motor skills in a small group of patients with Huntington's chorea.
Extrapyramidal Tracts↗
Extrapyramidal effects of neuroleptics.
A study was conducted on 66 psychiatric inpatients who took major tranquilizers for periods of four to 16 years. The frequency of signs of Parkinsonism and the effects of orphenadrine on these were studied in a double-blind crossover method. Sixty-one per cent of the patients showed signs of Parkinsonism. Female patients and those with organic brain pathology more frequently exhibited Parkinsonism (although the difference was not statistically significant). No correlation was found between duration of treatment and extrapyramidal effects. Of the 40 patients who developed Parkinsonism, 25 responded favourably to orphenadrine, while six (15%) had more marked manifestations on orphenadrine than on placebo.
Adult↗
Parkinsonian tremor loses its alternating aspect during non-REM sleep and is inhibited by REM sleep.
Non-REM sleep transforms the waking alternating Parkinsonian tremor into subclinical repetitive muscle contractions whose amplitude and duration decrease as non-REM sleep progresses from stages I to IV. During REM sleep Parkinsonian tremor disappears while the isolated muscle events increase significantly.
Adult↗
Extrapyramidalism in Alzheimer's disease: prevalence, psychiatric, and neuropsychological correlates.
The prevalence and clinical correlates of extrapyramidal signs in a consecutive series of 78 patients with Alzheimer's disease attending a neurology clinic, and 20 age comparable normal controls, were examined. Based on the unified Parkinson's disease rating scale (UPDRS) findings, 18 patients (23%) met criteria for parkinsonism, 44 (56%) had isolated extrapyramidal signs, and 16 (21%) had no extrapyramidal signs. Whereas the control group showed a similar prevalence of isolated extrapyramidal signs (57%), none of them showed parkinsonism. No significant differences were found for age, sex, duration of illness, and severity of dementia among the three Alzheimer's disease groups. Patients with Alzheimer's disease-parkinsonism, however, showed a significantly higher frequency of major depression and dysthymia and significantly higher Hamilton depression scores than patients with isolated or no extrapyramidal signs. Patients with Alzheimer's disease-parkinsonism also showed significantly more deficits on frontal lobe related tasks such as the Wisconsin card sorting test, trail making test, and verbal fluency, as well as on tests of constructional praxis and abstract reasoning than patients with Alzheimer's disease but no extrapyramidal signs. In conclusion, the study showed a specific association between Alzheimer's disease and parkinsonism, as well as significant relations between parkinsonism, deficits in executive functions, and depression among patients with Alzheimer's disease.
Aged↗
Clinical and magnetic resonance imaging study of extrapyramidal symptoms in multiple system atrophy.
Slit-hyperintensity in the outer margin of the putamen on T2 weighted MRI was found in 17 out of 28 patients with clinically diagnosed multiple system atrophy. Thirteen of these 17 patients showed extrapyramidal signs. Five patients had only unilateral slit-hyperintensity; four of them had contralateral rigidity; and one had bradykinesia. Despite mild rigidity, one case showed no slit-hyperintensity. One of the 14 cases with parkinsonism showed no hyperintensity, and four of the 14 cases without parkinsonism showed hyperintensity. On the other hand, slit-hyperintensity was not seen in any of 25 patients with clinically diagnosed Parkinson's disease. Putaminal slit-hyperintensity is a useful MRI feature in the differential diagnosis between Parkinson's disease and multiple system atrophy predominantly affecting the extrapyramidal system.
Aged↗
Motor and cognitive function in Lewy body dementia: comparison with Alzheimer's and Parkinson's diseases.
OBJECTIVE: Motor and cognitive function were compared in patients with Lewy body dementia, Parkinson's disease, or Alzheimer's disease, to identify features that may be clinically useful in differentiating Lewy body dementia from Alzheimer's disease and Parkinson's disease. METHODS: A range of neuropsychological function and extrapyrimidal signs (EPS) was assessed in 16 patients with Lewy body dementia, 15 with Parkinson's disease, 25 with Alzheimer's disease, and 22 control subjects. RESULTS: The severity of total motor disability scores increased in the following order: controls approximately = Alzheimer's disease << Parkinson's disease < Lewy body dementia. Compared with patients with Parkinson's disease, patients with Lewy body dementia had greater scores for rigidity and deficits in the finger tapping test, but rest tremor and left/right asymmetry in EPS were more evident in Parkinson's disease. Patients with Lewy body dementia were also less likely to present with left/right asymmetry in EPS at the onset of their parkinsonism. "Sensitivity" to neuroleptic drugs was noted in 33% of patients with Lewy body dementia. Alzheimer's disease and Lewy body dementia groups had greater severity of dementia compared with the Parkinson's disease group and controls. Neuropsychological evaluation disclosed severe but similar degrees of impaired performances in tests of attention (digit span), frontal lobe function (verbal fluency, category, and Nelson card sort test) and motor sequencing in both Lewy body dementia and Alzheimer's disease groups, than Parkinson's disease and controls. In the clock face test, improved performance was noted in the "copy" compared to "draw" part of the test in controls, patients with Alzheimer's disease, and those with Parkinson's disease, but not in the patients with Lewy body dementia, who achieved equally poor scores in both parts of the test. CONCLUSIONS: EPS in Lewy body dementia resemble those seen in idiopathic Parkinson's disease, although less rest tremor and left/right asymmetry but more severe rigidity favours a diagnosis of Lewy body dementia. The unique profile of patients with Lewy body dementia seen in the clock face test suggests that this simple and easy to administer test may be useful in the clinical setting to differentiate Lewy body dementia and Alzheimer's disease.
Aged↗