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 cholinergic neurons located within the pedunculopontine nucleus (Ch5) of patients with Alzheimer's disease (AD; n = 15), Parkinson's disease (PD; n = 2), and neurologically normal (n = 6) subjects were visualized immunohistochemically using choline acetyltransferase, pharmacohistochemically using acetylcholinesterase, or by reduced histochemical methods using nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d). Each histochemical procedure localized a well-delineated, compact lateral group and a more diffuse medial group of neurons within the pedunculopontine nucleus. Co-localization experiments revealed that all three enzymes marked the same population of cholinergic neurons. The extent of pathological alterations associated with the cholinergic neurons within the compact lateral sector of the pedunculopontine nucleus was examined in sections that reacted for NADPH-d, counterstained with thioflavin-S. The average number of neurofibrillary tangles within this portion of the pedunculopontine nucleus was 25.4 (range 0-70) in patients with AD, 1.5 (range 1-2) in those with PD, and 1.2 (range 0-4) in aged control subjects. Of the total number of neurofibrillary tangles counted in AD cases, 72.7% were end-stage ghosts and 27.3% were tangle-bearing neurons. The pathological alteration of cholinergic neurons of the compact lateral aspect of the pedunculopontine nucleus may play a role in some of the behavioral features characteristic of AD.
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PMID:Neurofibrillary tangles in cholinergic pedunculopontine neurons in Alzheimer's disease. 320 15

The substantia nigra (SN) receives afferents from cholinergic neurons of the pedunculopontine tegmental nucleus (PPTg), a neuronal population that shows high levels of nitric oxide synthase (NOS), the enzyme responsible for the synthesis of nitric oxide. We have investigated the effects of the injection in PPTg of two neurotoxins, kainic acid (an excitotoxic neurotoxin), and ethylcholine mustard azirinium ion (AF64A, a non-excitotoxic neurotoxin), upon the SN cells of the rat, by using choline acetyltransferase (ChAT) immunohistochemistry as a marker of cholinergic neurons, and nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry and NOS immunohistochemistry as markers of nitric oxide-producing neurons. Our results show that in normal rats, the SN contains two populations of NOS-positive neurons: large cholinergic neurons of PPTg that invade the caudal region of the SN, and small elongated neurons lying in the SN pars compacta. After ipsilateral PPTg lesion, another population of nigral cells, constituted by medium sized neurons, became NADPHd/NOS-positive. This was much more evident in AF64A-injected rats, in which many medium sized neurons showed enzymatic activity and normal morphological features, at least during the 90 days after injection. Kainic acid-injected rats, in contrast, showed nigral cell degeneration, an effect not found in AF64A material, and only a few NOS-positive neurons. NADPHd/NOS activity was never present in degenerating neurons. These findings suggest that induction of NOS activity is not involved in nigral cell degeneration, and that nitric oxide could have a protective rather than a neurotoxic role. The possible role of nitric oxide in the pathogenesis of Parkinson's disease is discussed.
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PMID:NOS expression in nigral cells after excitotoxic and non-excitotoxic lesion of the pedunculopontine tegmental nucleus. 951 71

The objective of the present study was to investigate the potential role of the free radical nitric oxide (NO) in the development of fetal rat mesencephalic neurons grafted in a 6-hydroxydopamine (6-OHDA) lesioned rat model of Parkinson's disease. First, using nitric oxide synthase (NOS)-immunocytochemistry and reduced nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry, we investigated the presence of the neuronal isoform of NOS (nNOS) in intrastriatal mesencephalic grafts. During the course of the experiment (16 weeks) an increase in the staining intensity and the number of nNOS/NADPH-d positive cells within the grafts was observed, as well as a gradual maturation of dopaminergic neurons. In addition, within both the host striatal and grafted mesencephalic tissue, a NO-dependent accumulation of cyclic guanosine monophosphate (cGMP) was detected, indicating the presence of guanylate cyclase, i.e., the target-enzyme for NO. Secondly, to determine the impact of NO on the survival of grafted dopaminergic neurons, 6-OHDA lesioned rats received mesencephalic grafts and were subsequently treated with the competitive NOS-inhibitor Nomega-nitro-l-arginine methylester (l-NAME). After chronic treatment for 4 weeks, tyrosine hydroxylase immunocytochemistry revealed no apparent differences between the survival of grafted dopaminergic neurons in control- or l-NAME treated animals, respectively. As the maturation of grafted dopaminergic neurons coincides with a gradual increase in the expression of nNOS within the graft and since dopaminergic cell numbers are not changed upon administration of l-NAME, it is concluded that endogenously produced and potentially toxic NO does not affect the survival of grafted fetal dopaminergic neurons.
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PMID:Sustained pharmacological inhibition of nitric oxide synthase does not affect the survival of intrastriatal rat fetal mesencephalic transplants. 959 18

Parkinson's disease (PD) is a neurodegenerative syndrome for which at present no cure is available; therapy consists mainly of amelioration of the symptoms with L-Dopa and/or dopamine (DA) agonists. Development of an effective causal therapy should be focussed on preventing or at least retarding the neurodegenerative process underlying the disease. At the cellular level, PD is characterized by degeneration of neuromelanin-containing dopaminergic neurons in the substantia nigra. Neuromelanin formation is the outcome of a process generally known as DA autooxidation, a chain of oxidation reactions in which highly neurotoxic DA-quinones are produced. The level of these DA-quinones, as estimated by the occurrence of their cysteinyl conjugates, is reported to be increased in the Parkinsonian substantia nigra. Hence, stimulation of pathways implicated in the detoxication of DA-quinones in the brain may provide neuroprotection in PD. Besides their inactivation through non-enzymatic antioxidants such as ascorbic acid and glutathione, DA-quinones are efficiently inactivated enzymatically by NAD(P)H:quinone oxidoreductase (NQO) and glutathione transferase(s), both of which are expressed in the human substantia nigra. The activity of these enzymes, which belong to the group of phase II biotransformation enzymes, can be up-regulated by a large variety of compounds. These compounds, including dithiolethiones, phenolic anti-oxidants, and isothiocyanates, have been shown to be active both in vitro and in vivo. Thus, considering the role of phase II biotransformation enzymes, in particular NQO and glutathione transferase(s), in the detoxication of DA-quinones, we propose that phase II enzyme inducers warrant evaluation on their neuroprotective potential in PD.
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PMID:Drug treatment of Parkinson's disease. Time for phase II. 1070 31

The autooxidation of L-Dopa, a catecholamine used in the symptomatic treatment of Parkinson's disease, generally yields reactive oxygen species and neurotoxic quinones. NAD(P)H:quinone oxidoreductase (NQO) is a flavoenzyme that is implicated in the detoxication of quinones, including those formed during L-Dopa autooxidation. Through the action of this enzyme, deleterious redox-labile quinones are turned into less toxic and more stable hydroquinones that are amenable to further detoxication and/or cellular excretion. In the present study, using primary rat astrocytes and C6 astroglioma as a model to evaluate the neuroprotective response of astroglial cells upon exposure to L-Dopa, we demonstrate that this compound, or more correctly its quinone (auto)oxidation products, up-regulates astroglial NQO in a time- and concentration-dependent way as assessed at the level of mRNA expression, protein level, and enzymatic activity. Moreover, under similar conditions cellular glutathione content was enhanced. It is concluded that, similar to glutathione, the oxidative stress limiting NQO is likely to contribute to the capacity of astroglial cells to protect dopaminergic neurons against L-Dopa, and, hence, may be considered as a potential target for the development of neuroprotective strategies for Parkinson's disease.
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PMID:L-Dopa stimulates expression of the antioxidant enzyme NAD(P)H:quinone oxidoreductase (NQO) in cultured astroglial cells. 1102 Jun 66

Individual vulnerability to reactive intermediates and oxidative stress accompanying metabolism of endogenous toxic compounds in the brain may promote the development of PD. Phase II detoxification enzymes such as glutathione S-transferase M1 (GSTM1), NAD(P)H:quinone oxidoreductase 1 (NQO1) and dihydronicotinamide riboside (NRH):quinone oxidoreductase 2 (NQO2) are important as cellular defenses against catecholamine-derived quinones and the oxidative stress that arises as a consequence of their metabolism. We conducted a study of the potential association between idiopathic Parkinson's disease and polymorphisms of GSTM1, NQO1, and NQO2. DNA samples from 111 unrelated outpatients with idiopathic PD and 100 unrelated healthy volunteers were analyzed. GSTM1 deletion polymorphism exhibited no positive association with PD (P = 0.596, odds ratio: 1.135), although GSTM1 were grouped into three genotypes (deletion/deletion, deletion/nondeletion, and nondeletion/nondeletion). In addition, polymorphism of the NQO1 gene caused by a C to T substitution in exon 3 presented no association with PD (P = 0.194, odds ratio: 1.31). However, polymorphism in the form of an insertion/deletion (I/D) of 29 base pairs (bp) nucleotides in the promoter region of the NQO2 gene, which contains four repeats of the putative core sequence (GGGCGGG) of the Sp1-binding cis-element, did associate with PD. The frequency of the D allele was significantly higher in patients with PD than in controls (P < 0.0001, odds ratio: 3.463). Our data suggested that the deletion of 29-bp nucleotides in the promoter region of the NQO2 gene associates with the development of PD.
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PMID:An association between idiopathic Parkinson's disease and polymorphisms of phase II detoxification enzymes: glutathione S-transferase M1 and quinone oxidoreductase 1 and 2. 1168 92

The commonest mitochondrial diseases are probably those impairing the function of complex I of the respiratory electron transport chain. Such complex I impairment may contribute to various neurodegenerative disorders e.g. Parkinson's disease. In the following, using hepatocytes as a model cell, we have shown for the first time that the cytotoxicity caused by complex I inhibition by rotenone but not that caused by complex III inhibition by antimycin can be prevented by coenzyme Q (CoQ1) or menadione. Furthermore, complex I inhibitor cytotoxicity was associated with the collapse of the mitochondrial membrane potential and reactive oxygen species (ROS) formation. ROS scavengers or inhibitors of the mitochondrial permeability transition prevented cytotoxicity. The CoQ1 cytoprotective mechanism required CoQ1 reduction by DT-diaphorase (NQO1). Furthermore, the mitochondrial membrane potential and ATP levels were restored at low CoQ1 concentrations (5 microM). This suggests that the CoQ1H2 formed by NQO1 reduced complex III and acted as an electron bypass of the rotenone block. However cytoprotection still occurred at higher CoQ1 concentrations (>10 microM), which were less effective at restoring ATP levels but readily restored the cellular cytosolic redox potential (i.e. lactate: pyruvate ratio) and prevented ROS formation. This suggests that CoQ1 or menadione cytoprotection also involves the NQO1 catalysed reoxidation of NADH that accumulates as a result of complex I inhibition. The CoQ1H2 formed would then also act as a ROS scavenger.
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PMID:Coenzyme Q cytoprotective mechanisms for mitochondrial complex I cytopathies involves NAD(P)H: quinone oxidoreductase 1(NQO1). 1206 6

The effects of dietary administration of capsaicin and rotenone on 4-nitroquinoline 1-oxide (4-NQO)-induced tongue tumorigenesis were investigated in male F344 rats. In pilot studies, gavage with capsaicin and rotenone elevated the phase II enzymes glutathione S-transferase (GST) and quinone reductase (QR), in the liver and tongue. Also, a 10 week period of feeding of 500 p.p.m. capsaicin or rotenone together with 4-NQO exposure inhibited the occurrence of tongue dysplasia. Subsequently, a long-term study was conducted to test the protective effects of both compounds on 4-NQO-induced tongue carcinogenesis. One group was treated with 4-NQO alone (20 p.p.m. in drinking water for 8 weeks) and four other groups received the carcinogen treatment plus diets containing 500 p.p.m. test compounds for 10 weeks (initiation phase) or for 28 weeks (post-initiation phase). At the termination of the study (38 weeks), feeding of rotenone during the initiation phase, but not during the post-initiation phase, was found to significantly reduce the incidence of tongue squamous cell carcinoma (53% vs. 16%, 70% reduction, P b=e 0.0250) and severe dysplasia (80% vs. 42%, 70% reduction, P = 0.028). Capsaicin feeding during either the initiation or promotion phase and rotenone feeding during the promotion phase also reduced the frequency of tongue carcinoma without statistical significance. The treatment with two compounds especially rotenone lowered cell proliferation activity in the tongue, elevated phase II enzymes' activities of the liver and tongue, and increased the apoptotic index of tongue carcinoma. Although our results suggest that rotenone feeding during the initiation stage prevented 4-NQO-induced tongue carcinoma, chronic intravenous exposure of rotenone reproduces several features of human Parkinson's disease in rats (Nat. Neurosci., 3, 1301-1306, 2000), suggesting that additional studies to confirm the safety of rotenone are warranted.
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PMID:Modifying effects of dietary capsaicin and rotenone on 4-nitroquinoline 1-oxide-induced rat tongue carcinogenesis. 1215 55

High levels of neuropeptide Y (NPY) are found in basal ganglia where it is co-localised with somatostatin (SOM) and nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH/d) in a population of striatal GABA containing interneurones. Although alterations occur in the levels of various neuropeptides in basal ganglia in Parkinson's disease (PD), it is not known whether NPY is affected. Using in situ hybridisation immunohistochemistry, we have examined the distribution of NPY mRNA in the caudate nucleus, putamen and nucleus accumbens of normal individuals and patients with PD. NPY mRNA was weakly expressed in the caudate nucleus, putamen and nucleus accumbens in normal individuals with a scattered labelling of neurones. However, there was no regional localisation within any brain area and no obvious differences between brain regions. In PD, the number of NPY mRNA-expressing cells was increased as was the density of the silver grains overlying each positive cell. The increase was more pronounced in the nucleus accumbens and in the ventral part of the caudate nucleus. The increase in NPY mRNA expression observed in patients with PD may reflect the loss of dopaminergic tone on striatal NPY containing interneurones, although a role for chronic L-DOPA therapy cannot be ruled out.
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PMID:Increased neuropeptide Y mRNA expression in striatum in Parkinson's disease. 1259 Nov 54

Parkinson's disease is a neurodegenerative disorder associated with selective loss of dopaminergic neurons in the substantia nigra. While the underlying cause of this cell death is poorly understood, oxidative stress is thought to play a role. We have previously shown that tetrahydrobiopterin (BH4), an obligatory co-factor for tyrosine hydroxylase (TH), exerts selective toxicity on dopamine-producing cells and that this is prevented by antioxidants. This study shows that BH4-induced dopaminergic cell death is primarily mediated by dopamine, evidenced by findings that (i) BH4 toxicity is increased in proportion to cellular dopamine content; (ii) non-dopaminergic cells become susceptible to BH4 upon exposure to dopamine; and (iii) depletion of dopamine attenuates BH4 toxicity in dopamine-producing cells. BH4 causes lipid peroxidation, suggesting involvement of oxidative stress but the toxicity does not require enzymatic oxidation of dopamine. Instead, it seems to involve formation of quinone product(s) because (i) the cell death is attenuated by exposure to or induction of quinone reductase and (ii) BH4-treated cells show increased formation of protein-bound quinones, which is inhibited by thiol antioxidants. These data taken together suggest that the presence of both BH4 and dopamine is important in rendering dopaminergic cells vulnerable and that this involves formation of reactive dopamine quinone products.
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PMID:Dopamine-dependent cytotoxicity of tetrahydrobiopterin: a possible mechanism for selective neurodegeneration in Parkinson's disease. 1280 34


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