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 neuropathology associated with Parkinson's disease (PD) is thought to involve excessive production of free radicals, dopamine autoxidation, defects in glutathione peroxidase expression, attenuated levels of reduced glutathione, altered calcium homeostasis, excitotoxicity and genetic defects in mitochondrial complex I activity. While the neurotoxic mechanisms are vastly different for excitotoxins and 1-methyl-4-phenylpyridinium ion (MPP(+)), both are thought to involve free radical production, compromised mitochondrial activity and excessive lipid peroxidation. We show here that the levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) increased significantly after treatment of cultured cerebellar granule cells (CGCs) with 50 microM MPP(+). Co-treatment with antioxidants such as ascorbate (ASC), catalase, alpha-tocopherol (alpha-TOH), coenzyme Q(10) (CoQ(10)) or superoxide dismutase (SOD) rescued the cells from MPP(+)-induced death. MPP(+)-induced cell death was also abolished by co-treatment with nitric oxide synthase (NOS) inhibitors such as 7-nitroindazole (7-NI), 2-ethyl-2-thiopseudourea hydrobromide (EPTU) or S-methylisothiourea sulphate (MPTU). We also tested the protective effects of an iron chelator (deferoxamine mesylate, DFx) and a peroxynitrite scavenger (FeTTPS) and the results lend further support to the view that the free radical cytotoxicity plays an essential role in MPP(+)-induced death in primary cultures of CGC.
 ...
PMID:Protection against MPP+ neurotoxicity in cerebellar granule cells by antioxidants. 1519 80

Parkinson's disease (PD) is a prevalent age-related motor dysfunction resulting from the hyperactivity of the indirect striatal pathway, which is controlled in an antagonistic manner by inhibitory dopamine D2 and facilitatory adenosine A(2A) receptors. Thus, dopamine precursors like l-DOPA are the standard therapy and A(2A) antagonists are now tested as anti-parkinsonians. Increased free radicals levels occur on aging and are proposed to be a contributing factor for PD. We now tested if free radicals affected A(2A) and D2 receptors in striatal membranes of young adult (2 months) and old (24 months) rats. The A(2A) receptor antagonist [3H]SCH 58261 bound to striatal membranes with a KD of 0.9 nM and a Bmax of 953 fmol/mg protein in young rats and with a KD of 0.8 nM and a Bmax of 725 fmol/mg protein in aged rats (24% decrease). The D2 receptor antagonist [3H]raclopride bound to striatal membranes with a KD of 4.0 nM and a Bmax of 598 fmol/mg protein in young rats and with a KD of 4.3 nM and a Bmax of 368 fmol/mg protein in aged rats (38% decrease). Exposure of striatal membranes to a free radical generation system (2 mM FeSO4 and 4 mM ascorbate) caused a similar decrease of [3H]SCH 58261 (35%) and [3H]raclopride (37%) binding in young adult rats but caused a greater decrease of [3H]SCH 58261 (49%) than of [3H]raclopride (20%) binding in aged rats. Thus, in aged rats, there is an unbalance of A(2A)/D2 receptor density favouring A(2A) receptors, which is restored on exposure to free radicals. This supports the hypothesis that the effectiveness of A(2A) receptor antagonists as anti-parkinsonians, demonstrated in young adult animals, may not be affected by a modified A(2A)/D2 receptor density in aged individuals suffering from exposure to increased free radical levels, as occurs in PD.
 ...
PMID:Effect of free radicals on adenosine A(2A) and dopamine D2 receptors in the striatum of young adult and aged rats. 1523 16

Nitric oxide (*NO) is a ubiquitous diffusible messenger in the central nervous system. *NO and derived nitrogen species may interact with catecholamines, thus, modifying not only its regulatory actions but also producing oxidants and free radicals that are likely to trigger toxic pathways in the nervous system. Oxidative pathways and chain oxidation reactions triggered by catecholamines may be broken by ascorbate and glutathione, of which there is ample supply in the brain. At the subcellular level, mitochondria and cytosolic dopamine storage vesicles are likely to provide site-specific settings for *NO and catecholamines interactions. Thus, a complex picture emerges in which the steady- state levels of the individual reactants, the rate constants of the reactions involved, the oxygen tension, and the compartmentalization of reactions determine the biological significance of the redox interactions between *NO and dopamine metabolism in the brain. The physiological relevance of *NO-driven chemical modifications of dopamine and its derivatives and the ensuing free radical production are discussed in connection with the neurodegeneration inherent in Parkinson's disease.
 ...
PMID:Redox interactions of nitric oxide with dopamine and its derivatives. 1569 85

We studied the effect of vitamin C, vitamin E, and beta carotene intake on the risk of Parkinson's disease (PD). We did a systematic review and meta-analysis of observational studies published between 1966 and March 2005 searching MEDLINE, EMBASE, and the Cochrane Library. Eight studies were identified (six case-control, one cohort, and one cross-sectional). We found that dietary intake of vitamin E protects against PD. This protective influence was seen with both moderate intake (relative risk 0.81, 95% CI 0.67-0.98) and high intake (0.78, 0.57-1.06) of vitamin E, although the possible benefit associated with high intake of vitamin E was not significant. The studies did not suggest any protective effects associated with vitamin C or beta carotene. We conclude that dietary vitamin E may have a neuroprotective effect attenuating the risk of PD. These results require confirmation in randomised controlled trials.
 ...
PMID:Intake of vitamin E, vitamin C, and carotenoids and the risk of Parkinson's disease: a meta-analysis. 1590 40

Chronic exposure to the pesticide rotenone induces a selective degeneration of nigrostriatal dopaminergic neurons and reproduces the features of Parkinson's disease in experimental animals. This action is thought to be relevant to its inhibition of the mitochondrial complex I, but the precise mechanism of this suppression in selective neuronal death is still elusive. Here we investigate the mechanism of dopaminergic neuronal death mediated by rotenone in primary rat mesencephalic neurons. Low concentrations of rotenone (5-10 nM) induce the selective death of dopaminergic neurons without significant toxic effects on other mesencephalic cells. This cell death was coincident with apoptotic events including capsase-3 activation, DNA fragmentation, and mitochondrial membrane depolarization. Pretreatment with coenzyme Q10, the electron transporter in the mitochondrial respiratory chain, remarkably reduced apoptosis as well as the mitochondrial depolarization induced by rotenone, but other free radical scavengers such as N-acetylcysteine, glutathione, and vitamin C did not. Furthermore, the selective neurotoxicity of rotenone was mimicked by the mitochondrial protonophore carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP), a cyanide analog that effectively collapses a mitochondrial membrane potential. These data suggest that mitochondrial depolarization may play a crucial role in rotenone-induced selective apoptosis in rat primary dopaminergic neurons.
 ...
PMID:Mitochondrial membrane depolarization and the selective death of dopaminergic neurons by rotenone: protective effect of coenzyme Q10. 1593 40

Parkinson's disease (PD) is the most common cause of parkinsonism. Parkinsonism is characterized by resting tremor, bradykinesia, rigidity and gait impairment. There is no specific diagnostic test for PD and it is important for clinicians to understand the clinical signs which help to distinguish PD from parkinsonism. It is equally important to be aware of the clinical signs which can be an indication that the diagnosis is not PD. These so-called Parkinson-plus syndromes include progressive supranuclear palsy (PSP), multiple systems atrophy (MSA), corticobasal degeneration (CBD), vascular parkinsonism (VP) and parkinsonism with dementia (Lewy body dementia, LBD). The differential diagnosis of parkinsonism will be discussed. Initiating pharmacologic therapy for PD must take into consideration the degree of dysfunction the patient is experiencing, the question of neuroprotection, the degree of motor response required, and the potential complications of long-term treatment. Neuropro-tective trials of coenzyme Q10 (CoQ), vitamin C, vitamin E, monoamine oxidase B inhibitors (MAO-I) and dopamine agonists do not support the use of any of these drugs for a neuroprotective effect. There is recent supportive evidence that levodopa may have a neuroprotective effect. Either dopamine agonists or levodopa may be initiated. Dopamine agonists are associated with fewer motor fluctuations and dyskinesias, while levodopa is associated with better motor performance. Initiation of therapy should be tailored to individual patients with the emphasis on symptom control, with the hope that new approaches to treatment of PD (including neuroprotection) will be forthcoming.
 ...
PMID:Parkinson's disease. Diagnosis and the initiation of therapy. 1617 58

Free radicals are reactive compounds that are naturally produced in the human body. They can exert positive effects (e.g. on the immune system) or negative effects (e.g. lipids, proteins or DNA oxidation). To limit these harmful effects, an organism requires complex protection - the antioxidant system. This system consists of antioxidant enzymes (catalase, glutathione peroxidase, superoxide dismutase) and non-enzymatic antioxidants (e.g. vitamin E [tocopherol], vitamin A [retinol], vitamin C [ascorbic acid], glutathione and uric acid). An imbalance between free radical production and antioxidant defence leads to an oxidative stress state, which may be involved in aging processes and even in some pathology (e.g. cancer and Parkinson's disease). Physical exercise also increases oxidative stress and causes disruptions of the homeostasis. Training can have positive or negative effects on oxidative stress depending on training load, training specificity and the basal level of training. Moreover, oxidative stress seems to be involved in muscular fatigue and may lead to overtraining.
 ...
PMID:Oxidative stress : relationship with exercise and training. 1657 58

Oral administration of 10% solution of Phytomix-40 (multicomponent plant phytoadaptogen) to C57Bl/6 mice with MPTP-induced Parkinson's syndrome alleviated symptoms (oligokinesia and muscle rigidity), compensated for the deficiency of dopamine and its metabolites (DOPAC and homovanillic acid), and reduced the level of lipid peroxides in the striatum. In vitro Phytomix-40 in a concentration of 3.3 x 10(-2) g/liter exhibited a pronounced antioxidant effect (5-fold decreased MDA level in mouse brain homogenate in Fe(2+)-ascorbate-dependent LPO).
 ...
PMID:Effect of complex phytoadaptogen on MPTP-induced Parkinson's syndrome in mice. 1718 Oct 52

As superoxide (.O2-) and hydroxyl radical (.OH) have been implicated in the pathogenesis of Parkinson disease, free radical scavenging and antioxidants have attracted attention as way to prevent progression of this disease. We examined the effects of eugenol, an essential oil extracted from cloves, on 6-hydroxydopamine (6-OHDA)-induced dopamine (DA) reduction in the mouse striatum. Eugenol administration 3 d before and 7 more days following one intracerebroventricular 6-OHDA injection prevented the reduction of striatal DA and its metabolites. Eugenol administration for 3 d reduced the increase of thiobarbituric acid-reactive substances (an indicator of lipid peroxidation) induced by ferric ion and increased glutathione (GSH) and L-ascorbate (Asc) in the striatum. Eugenol did not change the levels of catalase, glutathione peroxidase, or superoxide dismutase-like activities. Eugenol is known to have .O2- and .OH scavenging activities in vitro. These results suggest that eugenol prevents 6-OHDA-induced DA depression by preventing lipid peroxidation directly and indirectly (via stimulation of GSH and Asc generating systems). Furthermore, increased GSH may protect cell death by conjugating with p-quinone produced in 6-OHDA auto-oxidation. The effects of eugenol treatment in this model suggest its possible usefulness for the treatment of Parkinson disease.
 ...
PMID:Eugenol [2-methoxy-4-(2-propenyl)phenol] prevents 6-hydroxydopamine-induced dopamine depression and lipid peroxidation inductivity in mouse striatum. 1732 31

The mechanisms responsible for the progressive degeneration of dopaminergic neurons and pathologic iron deposition in the substantia nigra pars compacta of patients with Parkinson's disease (PD) remain unclear. Heme oxygenase-1 (HO-1), the rate-limiting enzyme in the oxidative degradation of heme to ferrous iron, carbon monoxide, and biliverdin, is upregulated in affected PD astroglia and may contribute to abnormal mitochondrial iron sequestration in these cells. To determine whether glial HO-1 hyper-expression is toxic to neuronal compartments, we co-cultured dopaminergic PC12 cells atop monolayers of human (h) HO-1 transfected, sham-transfected, or non-transfected primary rat astroglia. We observed that PC12 cells grown atop hHO-1 transfected astrocytes, but not the astroglia themselves, were significantly more susceptible to dopamine (1 microM) + H(2)O(2) (1 microM)-induced death (assessed by nuclear ethidium monoazide bromide staining and anti-tyrosine hydroxylase immunofluorescence microscopy) relative to control preparations. In the experimental group, PC12 cell death was attenuated significantly by the administration of the HO inhibitor, SnMP (1.5 microM), the antioxidant, ascorbate (200 microM), or the iron chelators, deferoxamine (400 microM), and phenanthroline (100 microM). Exposure to conditioned media derived from HO-1 transfected astrocytes also augmented PC12 cell killing in response to dopamine (1 microM) + H(2)O(2) (1 microM) relative to control media. In PD brain, overexpression of HO-1 in nigral astroglia and accompanying iron liberation may facilitate the bioactivation of dopamine to neurotoxic free radical intermediates and predispose nearby neuronal constituents to oxidative damage.
 ...
PMID:Astroglia overexpressing heme oxygenase-1 predispose co-cultured PC12 cells to oxidative injury. 1752 19


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