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

The TaqIA D2 dopamine receptor (DRD2) minor (A1) allele was first associated with severe alcoholism a decade ago. Since then, studies both confirming and not confirmnning this finding were reported. However, a meta-analysis of a large number of Caucasian alcoholics (both more severe and less severe) and controls (both assessed and unassessed for substance use disorders) revealed a significantly higher frequency (p < 10(-6)) and prevalence (p < 10(-8)) of the DRD2 A1 allele in the alcoholics. Further analysis showed that the more severe alcoholics had a 3-fold higher prevalence of the DRD2 A1 allele than the assessed controls (p < 10(-10)), whereas no difference was found between the less severe alcoholics and the unassessed controls. DRD2 exonic or promoter mutations have not yet been associated with alcoholism, although two intronic variants at the TaqIB and intron 6 sites, which are in linkage disequilibrium with the TaqIA site, were associated with this disorder. Variants of the DRD2 gene have also been associated with cocaine, nicotine and opioid dependence, obesity and gambling. It is hypothesised that the DRD2 is a reinforcement or reward gene. Although less intensively studied than substance use disorders, the DRD2 gene has been implicated in Tourette's syndrome (TS), post-traumatic stress disorder (PTSD) and certain symptoms associated with affective disorders and schizophrenia. Further, DRD2 variants have been implicated in Parkinson's disease (PD) and in iatrogenically-induced movement disorders, as well as in certain migraineurs. Phenotypic differences have been associated with DRD2 variants. These include reduced D2 dopamine receptor numbers and diminished glucose metabolism in the brain of subjects who carry the DRD2 A1 allele. In addition, phenotypic differences have been found in neurocognitive and personality characteristics, and in treatment outcome of DRD2 variants. The involvement of the DRD2 gene in certain neuropsychiatric disorders opens up the potential of a targeted pharmacogenomic approach to the prevention and treatment of these disorders.
 ...
PMID:The DRD2 gene in psychiatric and neurological disorders and its phenotypes. 1125 81

Georges Gilles de la Tourette's contribution to neurology goes beyond the description of the neurological disorder named after him. On December 28, 1885, he defended his doctoral thesis devoted to "gait in the diseases of the nervous system, studied by the method of imprints". In collaboration with Albert Londe, he worked for two years in Charcot's department on "a simple method applicable to both healthy and unhealthy patients", establishing the scientific and modern basis of functional exploration of human gait. The purpose was to "record the modifications of the gait and to fix them permanently, using suitable devises to guarantee not only rigorous comparison, but also to prevent observers, making use of the same method, from disputing or canceling the results completely independent of the experimenter himself". Georges Gilles de la Tourette defined the various characteristic parameters and provided the normal reference values in males and females, determining the physiological asymmetry of steps. He described spastic gait, shaking palsy, and locomotor ataxia. He distinguished between disorders of nervous control and related joint diseases. He also classified gait disorders occurring during hemiplegia. Modern development of kinetic, kinematic and biomechanical studies is a good illustration of the current relevancy of Gilles de la Tourette's contribution.
 ...
PMID:[Georges Gilles of Tourette, pioneer of gait analysis in the nervous system diseases]. 1131 91

Gilles de la Tourette syndrome (TS) is a basal ganglia (BG) disorder, associated not only with hyperkinetic movements but also with attentional impairments. This experiment sought to ascertain whether overt direct visual attention would influence tactile attentional performance in TS, via the use of a vibrotactile choice reaction time procedure involving biased probabilities of event occurrence. Participants were required to look (i.e., direct gaze) either at the hand receiving the most (expected) vibrations, or the hand less often stimulated (the unexpected), for both crossed and uncrossed arm postures. Contrary to our predictions, gaze did not influence attentional performance in TS patients. Furthermore, patients were found not to be sensitive to distributions of event probability; that is, they did not demonstrate normal expectancy effects like controls. Attentional deficits in TS (as in Parkinson's disease, another BG disorder) may pertain more to difficulties in holding rather than in shifting the focus of attention. Moreover, directing attention towards the unexpected locus in the crossed arm posture improved overall performance in both patients and controls, suggesting that increased task demands (e.g., crossed arm posture), and/or unexpected stimulus location, may be alleviated by directed attention. These impairments may stem from dysfunction in the circuits linking the frontal lobes with the BG.
 ...
PMID:Directed attention in Gilles de la Tourette syndrome. 1156 5

The dopamine system is known to be closely involved in brain neuronal dysfunction and in diseases such as Parkinson's disease, Tourette's syndrome, attention deficit hyperactive disorder, generation of pituitary tumors and schizophrenia. According to the classical dopamine hypothesis on the pathology of schizophrenia, conventional antipsychotics has D2 dopamine receptor antagonistic profiles. However, the use of typical antipsychotics has several limitations; that is, some patients do not respond to them, they can even worsen negative symptoms, and they can provoke unacceptable extrapyramidal and endocrine side effects. To produce effective antipsychotics with reduced side effects, partial agonists to D2 dopamine receptors (D2 receptors) have been developed. Despite the effectiveness of partial agonists for pre- and postsynaptic D2 receptors, administration of such drugs results in inconsistent clinical effects to ameliorate the symptoms of schizophrenia. Thus, strategies for obtaining ideal effective antipsychotics with reduced side effects are considered in this short review with respect to the intrinsic efficacies and affinities of the partial agonists, based on the partial agonist concept.
 ...
PMID:Strategy for modulation of central dopamine transmission based on the partial agonist concept in schizophrenia therapy. 1156 10

Charcot described many neurological diseases in the 19th century, particularly in movement disorders. Charcot contributed in the clinical description of Parkinson's disease, and introduced its first pharmacological treatment. He also studied the hyperkinesias, e.g. of Tourette syndrome, differential diagnosis of tremors, dystonias, choreas and startle disease. Marsden, who died recently, was an exponent in the study of Movement Disorders, with many publications in this field in the 20th century. His most important contributions are definitions and classifications of movement disorders, such as Parkinson's disease, dystonia, myoclonus, essential tremor, the description of the syndromes "Painful Legs Moving Toes", "Gait Ignition Failure" and "Primary Writing Tremor". The contributions of Charcot in the 19th century and Marsden in the 20th century to the movement disorders allow us to conclude that both of them were the most representative icons in this field in the past two centuries.
 ...
PMID:[Contributions of Charcot and Marsden to the development of movement disorders in the 19th and 20th centuries]. 1954 43

The substantia nigra is an important brain nucleus involved in the expression of movement disorders and seizures. The two most common movement disorders affecting the substantia nigra, Parkinson's disease and Tourette syndrome, show gender differences and age-related onset. To assess the substrates for the gender and age specificity of substantia nigra-related disorders, we determined the functional properties of the substantia nigra gamma-aminobutyric acid (GABAA) system along its anterior-posterior axis, using localized microinfusions of muscimol (a GABAA agonist) and susceptibility to motor seizures in rats. In the substantia nigra, there are sex-specific differences in the topographic segregation and functionality of GABAA systems. In mature male rats there are two distinct regions mediating opposite effects on seizures; in female rats there is only one region that can affect seizures. In the neonatal period, the presence of circulating testosterone is essential for the development of a substantia nigra region that exerts proconvulsant effects throughout the rat's life, a unique feature of the male substantia nigra. The final maturation of the substantia nigra occurs in the peripubertal period, and is in part regulated by testosterone as well. The recognition of the existence of distinct sex- and age-specific substantia nigra features can be translated into new cures of disorders affecting the substantia nigra.
 ...
PMID:Sexual dimorphism and developmental regulation of substantia nigra function. 1170 65

Following acceptance of clozapine as a superior antipsychotic agent with low risk of adverse extrapyramidal syndromes (EPS), such as dystonia, parkinsonism, akathisia or tardive dyskinesia, several novel antipsychotic drugs have been developed with properties modelled on those of clozapine. Though generally considered 'atypical' in their relatively low risk of inducing EPS, these agents vary considerably in their pharmacology and impact on neurological functioning. Although few comparative data are available, the atypical antipsychotics can be tentatively ranked by EPS risk (excluding akathisia and neuroleptic malignant syndrome) in the following order: clozapine < quetiapine < olanzapine = ziprasidone. At higher doses, risperidone is ranked with a higher EPS risk than olanzapine and ziprasidone, but its risk of EPS is lower with lower doses. In general, this ranking is inversely related to antidopaminergic (D2 receptor) potency. The high antiserotonergic (5-HT2A receptor) potency of risperidone, clozapine, ziprasidone and olanzapine, but not quetiapine, as well as the antimuscarinic activity of olanzapine and clozapine may also limit EPS. For the treatment of psychotic reactions to dopamine agonist therapy in Parkinson's disease, clozapine is both effective and relatively well tolerated; quetiapine may be tolerated, olanzapine is not well tolerated, risperidone is poorly tolerated, and amisulpride and ziprasidone have not been well evaluated. Clozapine, perhaps because of its anticholinergic activity, can reduce parkinsonian tremor. It is useful for ongoing psychosis with tardive dyskinesia, especially for dystonic features. No atypical antipsychotic is clearly effective for motor abnormalities in Huntington's disease or Tourette's syndrome, and the effect of these drugs on other neurological disorders have been well evaluated in only small numbers of patients. In summary, with the exception of clozapine, and perhaps quetiapine, atypical antipsychotics have brought only relative avoidance of EPS, strongly encouraging continued searches for novel antipsychotic agents.
 ...
PMID:Effects of newer antipsychotics on extrapyramidal function. 1177 17

The dopamine transporter gene (DAT) has been implicated in a variety of disorders, including bipolar disorder, attention-deficit hyperactivity disorder, cocaine-induced paranoia, Tourette's syndrome, and Parkinson's disease. As no clear functional polymorphism has been identified to date, studies rely on linkage disequilibrium (LD) to assess the possible genetic contribution of DAT to the various disorders. A better understanding of the complex structure of LD across the gene is thus critical for an accurate interpretation of the results of such studies, and may facilitate the mapping of the actual functional variants. In the process of characterizing the extent of variation within the DAT gene, we have identified a number of single nucleotide polymorphisms (SNPs) suitable for LD studies, 14 of which have been analyzed, along with a 3' repeat polymorphism, in a sample of 120 parent-proband triads. Calculations of pairwise LD between the SNPs in the parental haplotypes revealed a high degree of LD (P < 0.00001) in the 5' (distal promoter through intron 6) and 3' (exon 9 through exon 15) regions of DAT. This segmental LD pattern is maintained over approximately 27 kb and 20 kb in these two regions, respectively, with very little significant LD between them, possibly due to the presence of a recombination hotspot located near the middle of the gene. These analyses of the DAT gene thus reveal a complex structure resulting from both recombination and mutation, knowledge of which may be invaluable to the design of future studies.
 ...
PMID:Segmental linkage disequilibrium within the dopamine transporter gene. 1184 Mar 9

Sequences of movements are initiated abnormally in neurological disorders involving basal ganglia dysfunction, such as Parkinson's disease or Tourette's syndrome. The substantia nigra pars reticulata (SNpr) is one of the two primary output structures of the basal ganglia. However, little is known about how substantia nigra mediates the initiation of normal movement sequences. We studied its role in coding initiation of a sequentially stereotyped but natural movement sequence by recording neuronal activity in SNpr during behavioural performance of 'syntactic grooming chains'. These are rule-governed sequences of up to 25 grooming movements emitted in four predictable (syntactic) phases, which occur spontaneously during grooming behaviour by rats and other rodents. Our results show that neuronal activation in central SNpr codes the onset of this entire rule-governed sequential pattern of grooming actions, not elemental grooming movements. We conclude that the context of sequential pattern may be more important than the elemental motor parameters in determining SNpr neuronal activation.
 ...
PMID:Substantia nigra pars reticulata neurons code initiation of a serial pattern: implications for natural action sequences and sequential disorders. 1240 74

The author reviews the applications of transcranial magnetic stimulation (TMS) in a series of movement disorders--namely, Parkinson's disease, corticobasal degeneration, multiple system atrophy, progressive supranuclear palsy, essential tremor, dystonia, Huntington's chorea, myoclonus, the ataxias, Tourette's syndrome, restless legs syndrome, Wilson's disease, Rett syndrome, and stiff-person syndrome. Single- and paired-pulse TMS studies have been done mainly for pathophysiologic purposes. Repetitive TMS has been used largely for therapy. Many TMS abnormalities are seen in the different diseases. They concur to show that motor cortical areas and their projections are the main target of the basal ganglia dysfunction typical of movement disorders. Interpretation has not always been clear, and sometimes there were discrepancies and contradictions. Largely, this may be the result of the extreme heterogeneity of the methods used and of the patients studied. It is premature to give repetitive TMS a role in treatment. Overall, however, TMS gives rise to a new, outstanding enthusiasm in the neurophysiology of movement disorders. There is reason to predict that TMS, with its continuous technical refinement, will prove even more helpful in the near future. Then, research achievements are reasonably expected to spill over into clinical practice.
 ...
PMID:Applications of transcranial magnetic stimulation in movement disorders. 1243 85


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>