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 saga of harmful administration of levodopa (LD) in the treatment of Parkinson's disease (PD) resulted from outcomes of animal trials and cell culture studies. They were initiated after the clinical observation of onset of motor complications related to the short plasma half-life of the drug in PD patients. This discussion only partially considered a further aspect, which is associated with the long-term administration of LD. Chronic LD intake increases homocysteine plasma levels. This may support progression of the disease due to concomitant onset of neuropsychiatric symptoms and comorbidities (i.e., vascular disease). In the periphery, therapeutic approaches for this LD-mediated homocysteine increase are vitamin supplementation (i.e., folic acid or application of LD with an inhibitor of catechol-O-methyltransferase [COMT]). In the brain, a blood-brain trespassing precursor of folic acid or a centrally acting COMT inhibitor may represent hypothetical therapeutic approaches. This COMT inhibitor should be applied together with an oxidative stress reducing monoamine oxidase-B inhibitor, in order to force central dopamine metabolism further down via the methylation path. However, this may turn out to be a double-edged sword, since the inhibition of O-methylation with the COMT inhibitor may hypothetically contribute to increased N-methylation. Thus, endogenous tetrahydroisoquinolines may be transformed to neurotoxic N-methylated tetrahydroisoquinolines. These neurotoxic compounds were observed in cerebrospinal fluid and plasma of long-term LD-treated PD patients. They have a structure similar to 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine or its ion 1-methyl-4-phenylpyridinium, both of which are known to induce PD-like motor symptoms.
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PMID:Role of homocysteine in the treatment of Parkinson's disease. 1850 60

Several lines of evidence support the neuroprotective action of cyclooxygenase-2 (COX-2) inhibitors in various models of Parkinson's disease (PD). In the current study, we investigated the neuroprotective properties of several COX inhibitors against 1-methyl-4-phenylpyridinium (MPP+) in neuroblastoma Neuro 2A (N-2A) cells in vitro and the protection against degeneration of substantia nigra pars compacta (SNc) dopaminergic (DA) neurons after the administration of 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP) in C57/BL6 male mice. The data obtained demonstrate a lack of protective effects observed by COX 1-2 inhibitors ibuprofen and acetylsalicylic acid against MPP+ toxicity in N-2A, where piroxicam was protective in a dose dependent manner (MPP+ control: 15 +/- 2% MPP+ piroxicam: 5 mM 89 +/- 4%). The data also indicate a drop in mitochondrial oxygen (O(2)) consumption and ATP during MPP+ toxicity with no restoration of mitochondrial function concurrent to a heightened concentration of somatic ATP during piroxicam rescue. These findings indicate that the neuroprotective effects of COX inhibitors against MPP+ are not consistent, but that piroxicam may work through an unique mechanism to propel anaerobic energy metabolism. On the other hand, using mice, piroxicam (20 mg/kg) was effective against MPTP-induced dopaminergic degeneration in the (SNc) and loss of locomotive function in mice. Administering a 3 day pre-treatment of piroxicam (20 mg/kg) was effective in antagonizing the losses in SNc tyrosine hydroxylase protein expression, SNc DA concentration and associated anomaly in ambulatory locomotor activity. It was concluded from these findings that piroxicam is unique among COX inhibitors in providing very significant neuroprotection against MPP+ in vitro and in vivo.
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PMID:The effects of piroxicam in the attenuation of MPP+/MPTP toxicity in vitro and in vivo. 1861 14

In the case of Parkinson's disease (PD), classical animal models have utilized dopaminergic neurotoxins such as 6-hydroxydopamine (6OHDA) and 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP). More recently, human genetic linkage studies have identified several genes in familial forms of PD. Transgenic models have been made that explore the function of PD-linked genes (e.g. alpha-synuclein, DJ-1, LRRK2, Parkin, UCH-L1, PINK1). Recent evidence suggests mitochondrial dysfunction may play a major role in PD. Manipulation of mitochondrial respiratory genes (e.g. mitochondrial transcription factor A or TFAM) also elicits a PD phenotype in mice. Transgenic mice (MitoPark) were developed that have TFAM selectively knocked out in dopaminergic neurons. The nigral dopamine neurons of MitoPark mice show respiratory chain dysfunction, accompanied by the development of intraneuronal inclusions and eventual cell death. In early adulthood, the MitoPark mice show a slowly progressing loss of motor function that accompanies these cellular changes. The MitoPark mouse enables further study of the role of mitochondrial dysfunction in DA neurons as an important mechanism in the development of PD. Transgenic technology has allowed new insights into mechanisms of neurodegeneration for a number of neurological disorders. This paper will summarize recent studies on several transgenic models of PD.
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PMID:Transgenic rodent models of Parkinson's disease. 1864 40

Genital dysfunction and testosterone deficiency occur frequently in Parkinson's disease and represent a typical non-motor symptom of the disorder. Despite that, to our knowledge no study investigated whether at experimental level this can be reproduced with classic Parkinsonism-inducing neurotoxins. In this study we evaluated the effects produced in the testis following administration of the Parkinsonism-inducing neurotoxin 1-methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine in mice. At 7 days following treatment, in the presence of a severe nigrostriatal dopamine depletion, we found a marked decrease in testosterone plasma levels in 1-methyl, 4-phenyl, 1,2,3,6-tetrahydropyridine-treated mice. Such testosterone loss occurred concomitantly with loss of Leydig cells and the presence of altered morphology in the interstitium with severe mitochondrial degeneration in spared Leydig cells. The loss of Leydig cells was accompanied by a marked decrease in TH immunohistochemistry and TH protein in the interstitium. This was accompanied by a significant decrease in norepinephrine levels in the testis. These effects shed novel light to understand genital dysfunction and testosterone deficiency in Parkinsonism, while offering a new experimental model to reproduce genital dysfunction in Parkinson's disease.
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PMID:MPTP-induced Parkinsonism is associated with damage to Leydig cells and testosterone loss. 1864 55

Pathophysiology of idiopathic Parkinson's disease (PD) is associated with degeneration of dopaminergic neurons and inflammatory responses in the mid-brain substantia nigra (SN). However, central dopaminergic replenishment therapeutic strategy with L-3,4-dihydroxyphenylalanine (L-DOPA), the precursor for dopamine synthesis, does not fully rescue these cells in SN or improve motor function. Besides, prolonged use of L-DOPA worsens the clinical symptoms in PD patients. Thus, there is a possibility that other areas of central nervous system may also be affected in this disease. Spinal cord, the final coordinator of movement in the central nervous system, may be one such site that is critically affected during pathogenesis of this complex movement disorder. In this review, we summarize the evidence in support of involvement of calpain, a Ca(2+)-activated non-lysosomal protease, in spinal cord degeneration in two models of experimental parkinsonism induced by the neurotoxin 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine and also the environmental toxin rotenone. The key focus of this review is to discuss the role that calpain plays in disrupting the structural and functional integrity of the spinal cord in these experimental models of parkinsonism. A similar disruptive role of calpain has been reported earlier in SN of PD patients as well as in experimental PD animals. Studies in rodent and cell culture models of PD suggest that treatment with calpain inhibitors (e.g., calpeptin, MDL-28170) can prevent neuronal death and restore functions. Furthermore, the degradation of calpain substrates in both brain and spinal cord during pathogenesis of PD suggested a putative role of calpain, and calpain inhibition as a therapeutic strategy in PD.
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PMID:Calpain as a potential therapeutic target in Parkinson's disease. 1867 14

Rigidity is a cardinal symptom of Parkinson's disease and is frequently used as an outcome measure in clinical and non-human primate studies examining the effects of medication or surgical intervention. A limitation of current rigidity assessment methods is that they are inherently subjective. To better understand the physiological mechanisms of rigidity and how various therapeutic approaches work, a more objective and quantitative method is needed. In this study, an automated arm rigidity testing (ART) system was developed to objectively quantify rigidity while the primate's limb was moved between two user-specified angles. Recordings of normal force versus elbow-angle were categorized according to area and slope. These quantitative measures of rigidity were investigated in three rhesus macaque monkeys treated with 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine and compared with clinical assessment methods. The ART system incorporates electromyographical recordings that can detect and differentiate active from actual resistance. The ART system detected significant changes in rigidity measures following administration of apomorphine or deep brain stimulation of the globus pallidus internus. The most sensitive measures were total area, extension slope, and flexion slope. The ART system provides precise and reliable measures of rigidity that are objective and quantitative.
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PMID:Objective quantification of arm rigidity in MPTP-treated primates. 1893 79

Appearance of dyskinesia is a common problem of long-term l-DOPA treatment in Parkinson's disease patients and represents a major limitation for the pharmacological management of the motor symptoms in advanced disease stages. We have recently demonstrated that dopamine released from serotonin neurons is responsible for l-DOPA-induced dyskinesia in 6-hydroxydopamine (6-OHDA)-lesioned rats, raising the possibility that blockade of serotonin neuron activity by combination of 5-HT(1A) and 5-HT(1B) agonists could reduce l-DOPA-induced dyskinesia. In the present study, we have investigated the efficacy of 5-HT(1A) and 5-HT(1B) agonists to counteract l-DOPA-induced dyskinesia in 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine (MPTP)-treated macaques, the gold standard model of Parkinson's disease. In addition, we have studied the ability of this treatment to prevent development of l-DOPA-induced dyskinesia in 6-OHDA-lesioned rats. The results demonstrate the existence of a potent synergistic effect between 5-HT(1A) and 5-HT(1B) agonists in their ability to dampen l-DOPA-induced dyskinesia in the MPTP-treated macaques. Sub-threshold doses of the drugs, which individually produced no effect, were able to reduce the abnormal involuntary movements by up to 80% when administered in combination, without affecting the anti-parkinsonian properties of l-DOPA. Furthermore, chronic administration of low doses of the 5-HT(1) agonists in combination was able to prevent development of dyskinesia, and reduce the up-regulation of FosB after daily treatment with l-DOPA in the rat 6-OHDA model. Our results support the importance of a clinical investigation of the effect of 5-HT(1A) and 5-HT(1B) agonists, particularly in combination, in dyskinetic l-DOPA-treated Parkinson's disease patients.
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PMID:Combined 5-HT1A and 5-HT1B receptor agonists for the treatment of L-DOPA-induced dyskinesia. 1895 77

It is widely known that the pathophysiology of idiopathic Parkinson's disease (PD) is associated with neurodegeneration and inflammatory responses in the midbrain substantia nigra. However, the possibility of neurodegeneration and inflammatory responses in other areas of the central nervous system (CNS) in course of the pathogenesis of PD remains to be explored. In this investigation, we provide evidence in support of the hypothesis that spinal cord, the final coordinator of movement, is also involved during parkinsonian degeneration using two distinct experimental parkinsonism models induced by the neurotoxin 1-methyl-4-phenyl 1,2,3,6-tetrahydropyridine (MPTP) and the environmental toxin rotenone. A key focus of our study is the role that calpain, a Ca(2+)-activated neutral protease, plays in disrupting the structural-functional integrity of the spinal cord in the context of spinal cord degeneration in experimental parkinsonism. We examined the mechanisms of calpain-mediated neuronal death in differentiated spinal cord motoneuron cultures following exposure to the active parkinsonian toxins 1-methyl-4-phenyl-pyridinium ion (MPP(+)) and rotenone and also tested the neuroprotective efficacy of calpeptin, a calpain inhibitor, in these cell culture models of experimental parkinsonism. Our results implied that spinal cord motoneurons could be a potential extranigral target of neurodegeneration during pathogenesis of PD in the CNS and that calpain inhibition could provide neuroprotection.
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PMID:Extranigral neurodegeneration in Parkinson's disease. 1899 78

Exposure to 1-methyl 4-phenyl 1,2,3,6-tetrahydropyridine (MPTP) induces dopaminergic neurodegeneration in the nigrostriatal pathway and nicotine and caffeine ameliorate neurodegenerative changes in MPTP-lesioned mouse model of Parkinson's disease (PD). The present study was undertaken to investigate the effect of nicotine and caffeine on the expression patterns of genes in the striatum of control and MPTP-treated mice to identify the differentially expressed transcripts and to assess their possible implications in neuroprotection. Mice were treated intraperitoneally with caffeine (20mg/kg) or nicotine (1mg/kg), daily, for the first 8 weeks followed by MPTP (20mg/kg) co-treatment for further 4 weeks along with respective controls. RNA was isolated from the striatum of control and treated mice; reverse transcribed separately into labeled cDNA and a mixture of equal quantities of labeled cDNA was hybridized with mouse 15k array. The expression levels of toll-interleukin-1 receptor domain-containing adaptor protein, nuclear protein-1, cathepsin B, interleukin-4 receptor, caspase 9, complement component-1, heat shock protein-1 and cytochrome c-oxidase-VIIc were validated by quantitative real-time polymerase chain reaction (qRT-PCR). MPTP differentially regulated the expression of many genes involved in apoptotic cell death, oxidative stress, cell cycle regulation, protein modification and mitochondrial dysfunction. The expression patterns of many of these transcripts were significantly restored in caffeine- and nicotine-treated mice. The results demonstrate the involvement of multiple molecular events in MPTP-induced toxicity and nicotine or caffeine-mediated neuroprotection.
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PMID:Nicotine- and caffeine-mediated changes in gene expression patterns of MPTP-lesioned mouse striatum: Implications in neuroprotection mechanism. 2023 Aug 7

Cognitive deficits, including attention and working memory deficits, are often described in Parkinson's disease (PD) patients even during the early stages of the disease. However, cognitive deficits associated with PD have proven difficult to treat and often do not respond well to the dopaminergic therapies used to treat the motor symptoms of the disease. Chronic administration of low doses of the neurotoxin 1-methy,4-phenyl,1,2,3,6-tetrahydropyridine (MPTP) can induce cognitive dysfunction in non-human primates, including impaired performance on a variable delayed response (VDR) task with attentional and memory components. Since alpha-2 adrenergic receptor agonists have been suggested to improve attention and working memory in a variety of conditions, the present study assessed the extent to which the alpha-2 noradrenergic agonist clonidine might influence VDR performance in early Parkinsonian non-human primates. Clonidine (0.02-0.10 mg/kg) improved performance on both attentional and memory components of the task, performed in a modified Wisconsin General Test Apparatus, in a dose-dependent manner and the cognition enhancing effects of clonidine were blocked by co-administration of the alpha-2 noradrenergic antagonist idazoxan (0.10 mg/kg). These data suggest that clonidine or drugs of this class, perhaps with greater receptor subtype selectivity and low sedation liability, might be effective therapeutics for cognitive dysfunction associated with PD.
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PMID:Clonidine improves attentional and memory components of delayed response performance in a model of early Parkinsonism. 2034 76


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