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)

Spasticity in man is presented as a disinhibition of spinal cord mechanisms, the responses to stretch depending on the interaction of the reflex effects of group Ia with those of group II afferent fibres. The reflex responses to muscle stretch and shortening in Parkinson's disease do not depend on an abnormality of spinal reflex mechanisms. The superimposition of physiological tremor or alternating tremor in rigidity produces the classical cog-wheel sensation. The phase lead of the action tonic stretch reflex was found to be reduced in patients with athetosis and cerebellar disease, thus diminishing damping of unwanted movements. The more complex transmission characteristics of the action tonic stretch reflex of normal man are absent in patients with spasticity and cerebellar lesions, presumably due to interference with long-loop pathways. In normal subjects gain of the reflex loop increases with voluntary contraction but in spasticity gain remains high irrespective of contraction level.
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PMID:A physiological approach to motor disorders. 15 18

The triad of rigidity, fever, and elevation of serum creatine phosphokinase (CPK) levels, labeled 'neuroleptic malignant syndrome' (NMS), is a dangerous complication of neuroleptic drug treatment. Amantadine was introduced for the pharmacological management of NMS because of its beneficial effects in Parkinson's disease which were attributed to direct or indirect dopaminomimetic properties of amantadine. While the dopaminomimetic effects of amantadine are weak under experimental conditions, recent studies have confirmed that amantadine is an antagonist at the N-methyl-D-aspartate (NMDA) type of glutamate receptor. Two lines of evidence suggest that amantadine or other NMDA receptor antagonists could be effective drugs for the reversal of NMS symptoms. First, glutamate antagonists restore the balance between glutamatergic and dopaminergic systems when dopaminergic transmission has been antagonized by neuroleptic drugs. Second, by virtue of their effects against rigor and spasticity, NMDA antagonists may reduce increased muscle tone and prevent rhabdomyolysis. In conclusion, NMS may be considered an iatrogenic excitatory aminoacid syndrome which is amenable to NMDA receptor antagonist therapy.
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PMID:A rationale for NMDA receptor antagonist therapy of the neuroleptic malignant syndrome. 133 36

After incubation of rat cortical cell cultures with the human immunodeficiency virus type 1 (HIV-1) coat protein gp120 for 12 h, cells showed fragmentation of DNA at internucleosomal linkers, the characteristic feature of apoptosis. In a quantitative approach, it was determined that the percentage of DNA fragmentation increased from 7%, in the absence of gp120, to 62% following incubation with 24 ng/ml of gp120. Simultaneously, the percentage of viable cells decreased from 94% to 33%. Memantine (1-amino-3,5-dimethyladamantane), a drug currently used in the therapy of spasticity and Parkinson's disease as well as the NMDA antagonist MK-801 both prevented the effects of gp120 at micromolar concentrations. In human cultured astrocytes, gp120 was ineffective with respect to DNA fragmentation and cell toxicity. From these data, we conclude that the gp120-induced apoptosis may contribute to the neurological complications frequently associated with the immunodeficiency syndrome. The cytoprotective effect of memantine in cortical cell cultures may qualify the drug for the treatment of AIDS-related dementia.
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PMID:gp120 of HIV-1 induces apoptosis in rat cortical cell cultures: prevention by memantine. 142 20

Recent electrophysiological studies in patients with cranial dystonia (CD) have demonstrated evidence for hyperactivity of brainstem interneurons. Tizanidine (Tz), a centrally acting skeletal muscle relaxant, is thought to act by antagonizing the activity of excitatory interneurons which mediate hypertonic processes (e.g. spasticity). Theoretically this agent may be effective in patients with CD. Ten patients were enrolled in an open-label study with a single-blind placebo wash-in. Eight patients tolerated doses of between 28-36 mg per day. For the most part tizanidine was ineffective for the symptoms of CD. This failure suggests that the reported brainstem interneuronal disturbances may not be altered by Tz. Further studies using concomitant electrophysiological assessment would be necessary to assess this possibility. Alternatively, these disturbances may not be a principle cause of the dystonic movements. The finding of similar changes in other basal ganglia diseases lacking CD (e.g. Parkinson's disease) favours this latter explanation.
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PMID:Tizanidine in cranial dystonia. 159 39

The purpose of this article is fourfold. First, a theory of motor control--the dual-strategy hypothesis--is outlined. Second, the methodologies and theoretical framework that are used to develop this theory are examined. Third, motor dysfunction is discussed in the context of this theory. In particular, Down syndrome, Parkinson's disease, cardiovascular accidents, and spasticity are discussed. Finally, potential applications of the theory to physical therapy are considered.
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PMID:Strategies underlying the control of disordered movement. 182 77

Hand muscle reflexes to stretch or electric stimulation of mixed nerves consist of two main components, the short latency reflex (SLR, M1) or Hoffmann reflex (HR) and the long latency reflex (LLR, M2). The SLR is most likely a spinal, monosynaptic reflex and all the evidence presently available supports a transcortical pathway of the LLR. Investigations in normal subjects demonstrate that the LLR is a reflex mediated by fast conducting muscle and cutaneous afferents. Group II muscle afferents do not significantly contribute to this reflex and it cannot be explained by repetitive excitation of spinal oligosynaptic pathways. These findings should not be uncritically generalized to other muscle groups, because the central and peripheral mechanisms apparently differ according to the body region and mode of stimulation. The LLR of hand muscles is most likely involved in skillful movements of the fingers. It is believed to assist rapid compensatory responses to unexpected disturbances. In addition to the main component of the LLR, which is called LLR II, the study of electrically elicited thenar reflexes following stimulation of the median nerve disclosed further LLR components, the LLR I and the LLR III. The latter reflexes are rarely seen in normal subjects but have a significance in several diseases. Several abnormalities could be demonstrated in different diseases. Enhanced HR and reduced LLR are found in spasticity of various origin. Enhanced LLR I are frequently seen in Parkinson's disease, essential tremor and reflex myoclonus. Absent or reduced LLR II is found in Huntington's disease and in different focal brain lesions but not in symptomatic choreatic syndromes of other origin. Delayed latencies of the LLR II or absent LLR II have been described in multiple sclerosis. Enhanced LLR III may occur in cerebellar diseases. The method to elicit LLR of thenar muscles by electric stimulation may prove to be useful for clinical neurophysiology.
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PMID:Physiology and clinical applications of hand muscle reflexes. 228 56

1. Monkeys with surgical unilateral ventromedial tegmental lesions of the brain stem served as models for investigating abnormalities in Parkinson's disease and Lesch-Nyhan syndrome. 2. The animals exhibited some neurological deficits which are similar to those observed in Parkinson's disease or Lesch-Nyhan syndrome. 3. In monkeys with unilateral ventrolateral tegmental lesions, the levels of dopamine and the activities of catecholamine-synthesizing enzymes were reduced on the lesion side of the striatum, and hypokinesia and tremor developed on the contralateral extremities. 4. Dopa or dopamine agonists relieve tremor and evoke abnormal involuntary movements which are similar to the responses observed in patients with Parkinson's disease. 5. The antitremor effect of Dopa is potentiated by catechol-O-methyltransferase inhibition, suggesting a therapeutic potential for these types of agents. 6. Evidence was obtained that stimulation of D2 dopamine receptors by selective dopamine agonists exerts antitremor activity and evokes abnormal involuntary movements. 7. Combined administration of D1 and D2 dopamine agonists seems to enhance the antitremor activity. 8. Partial dopamine agonists exert antitremor activity and produce less severe abnormal involuntary movements than full dopamine agonists. 9. In a group of monkeys with unilateral ventromedial tegmental lesions of the brain stem the administration of mixed D1/D2 dopamine agonists results in the occurrence of self-biting behavior of the forelimb digits and spasticity of the hindlimbs and these symptoms are similar to those observed in patients with Lesch-Nyhan syndrome. 10. The self-biting behavior seems to be associated with the stimulation of central D1 dopamine receptors and therefore the possible involvement of dopamine neuronal abnormalities in Lesch-Nyhan syndrome deserves further investigation.
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PMID:Monkeys with unilateral ventromedial tegmental lesions of the brain stem: models for Parkinson's disease and Lesch-Nyhan syndrome. 250 25

Wartenberg developed his pendulum test as a simple but precise test to assist examination of muscle tone in patients with Parkinson's disease. It has recently been reintroduced, and computerised, to evaluate spasticity in young hemiplegics. The results are reported on the highly successful application of this computerised test to large numbers of healthy, elderly subjects. The data have provided normal values for a number of measurements. Analysis of variance has shown that differences between individual subjects account for a major part of the total variabilities seen in all measurements taken. Factors such as position, leg and time trend contribute very little to total variation and, for practical purposes, can be ignored.
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PMID:Observations on the applicability of the Wartenberg pendulum test to healthy, elderly subjects. 322

In this review, the authors present a critical overview of the historical development, indications, complications, operative techniques, and results of procedures for the alleviation of the major dyskinesias. Emphasis is placed upon recent refinement of technique, particularly stereotaxis, as well as neurophysiologic stimulation and recording, computerized tomographic scanning (CT) and magnetic resonance imaging (MRI). Specific disorders that may be amenable to surgical therapy include spasticity secondary to spinal cord pathology, cerebral palsy, and multiple sclerosis; the tremor and rigidity of Parkinson's disease; essential tremor; dystonia; spasmodic torticollis; post-traumatic and postinfarction intention tremor; cerebral palsy with tremor; hemiballismus; myoclonus; and dyskinesias induced by L-DOPA.
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PMID:Neurosurgical management of spasticity, rigidity, and tremor. 332 80

The influence of memantine on several properties of a neuronal cell line was tested. The aim was to get some insight into possible mechanisms of action of this drug which is therapeutically applicable in treatment of spasticity, Parkinson's disease, and cerebral coma. In neuroblastoma X glioma hybrid cells, memantine, at micromolar concentrations, blocked the depolarization induced by iontophoretically applied serotonin (5-hydroxytryptamine, 5-HT). In the hybrid cells, receptors of the 5-HT3 type mediated the depolarization, which was frequently accompanied by a series of action potentials. The inhibition by memantine of the serotonin response occurred fast and was completely reversible, irrespective of whether the cell showed a stable membrane potential or spontaneous action potentials. However, memantine did not alter spontaneous or electrically evoked action potential activity in the hybrid cells, and apparently did not block the underlying ionic conductances. Furthermore memantine did not affect either the cation permeability activated by substance P in the hybrid cells or the K+ channel triggered by bradykinin in a glioma cell line. Thus, memantine appears specifically to suppress the ion channel opened by serotonin in the hybrid cells. The interaction of memantine with serotonin receptors and the associated ion channels reported here, might give an important clue, as to a site of action of memantine in the nervous system.
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PMID:Memantine (1-amino-3,5-dimethyladamantane) blocks the serotonin-induced depolarization response in a neuronal cell line. 335 74


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