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)

It is well established that in the CNS, endogenous adenosine plays a pivotal role in neurodegeneration. A low, nanomolar concentration of adenosine is normally present in the extracellular fluid, but it increases dramatically during enhanced nerve activity, hypoxia or ischemia. In these pathological conditions, adenosinergic transmission-potentiating agents, which elevate adenosine level by either inhibiting its degradation (adenosine deaminase and kinase inhibitors) or preventing its transport, offer protection against ischemic or excitotoxic neuronal damage. The directly acting adenosine A1 receptor agonists are known to mediate neuroprotection, mostly by the blockade of Ca2+ influx, which results in the inhibition of glutamate release and reduction of its excitatory effects at a postsynaptic level. More recent data have shown that antagonists of adenosine A2A receptors markedly reduce cerebral ischemic damage in animal models of focal and global ischemia. Moreover, these compounds attenuate the neuronal loss induced by excitatory amino acids (EAA). A neuroprotective effect of adenosine A2A receptor antagonists was also shown in animal models of Parkinson's disease (MPTP, 6-OHDA, methamphetamine). Hence, it might be suggested that adenosine A2A receptor antagonists may represent a novel strategy in the therapeutic approach to pathologies characterized by acute or chronic neurodegenerative events, since they not only reverse motor impairment but can act as neuroprotective compunds by promoting cell survival.
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PMID:Neuroprotective role of adenosine in the CNS. 1252 85

Historically, 3,4-dihydroxyphenylalanine (DOPA) has been believed to be an inert amino acid that alleviates the symptoms of Parkinson's disease by its conversion to dopamine via the enzyme aromatic L-amino acid decarboxylase. In contrast to this generally accepted idea, we propose that DOPA itself is a neurotransmitter and/or neuromodulator, in addition to being a precursor of dopamine. Several criteria, such as synthesis, metabolism, active transport, existence, physiological release, competitive antagonism, and physiological or pharmacological responses, must be satisfied before a compound is accepted as a neurotransmitter. Recent evidence suggests that DOPA fulfills these criteria in its involvement mainly in baroreflex neurotransmission in the lower brainstem and in delayed neuronal death by transient ischemia in the striatum and the hippocampal CA1 region of rats.
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PMID:L-3,4-Dihydroxyphenylalanine as a neurotransmitter candidate in the central nervous system. 1255 86

Nerve growth factor was the first identified protein with anti-apoptotic activity on neurons. This prototypic neurotrophic factor, together with the three structurally and functionally related growth factors brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT3) and neurotrophin-4/5 (NT4/5), forms the neurotrophin protein family. Target T cells for neurotrophins include many neurons affected by neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and peripheral polyneuropathies. In addition, the neurotrophins act on neurons affected by other neurological and psychiatric pathologies including ischemia, epilepsy, depression and eating disorders. Work with cell cultures and animal models provided solid support for the hypothesis that neurotrophins prevent neuronal death. While no evidence exists that a lack of neurotrophins underlies the etiology of any neurodegenerative disease, these studies have spurred on hopes that neurotrophins might be useful symptomatic-therapeutic agents. However first clinical trials led to variable results and severe side effects were observed. For future therapeutic use of the neurotrophins it is therefore crucial to expand our knowledge about their physiological functions as well as their pharmacokinetic properties. A major challenge is to develop methods for their application in effective doses and in a precisely timed and localized fashion.
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PMID:Neurotrophins. 1257 26

The evidence for a role of apoptosis in the neurodegenerative diseases, Alzheimer's disease (AD), Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS), and in the more acute conditions of cerebral ischemia, traumatic brain injury (TBI), and spinal cord injury (SCI) is reviewed with regard to potential intervention by means of small antiapoptotic molecules. In addition, the available animal models for these diseases are discussed with respect to their relevance for testing small antiapoptotic molecules in the context of what is known about the apoptotic pathways involved in the diseases and the models. The principal issues related to pharmacotherapy by apoptosis inhibition, i.e., functionality of rescued neurons and potential interference with physiologically occurring apoptosis, are pointed out. Finally, the properties of a number of small antiapoptotic molecules currently under clinical investigation are summarized. It is concluded that the evidence for a role of apoptosis at present is more convincing for PD and ALS than for AD. In PD, damage to dopaminergic neurons may occur through oxidative stress and/or mitochondrial impairment and culminate in activation of an apoptotic, presumably p53-dependent cascade; some neurons experiencing energy failure may not be able to complete apoptosis, end up in necrosis and give rise to inflammatory processes. These events are reasonably well reflected in some of the PD animal models, notably those involving 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and rotenone. In sporadic ALS, an involvement of pathways involving p53 and Bcl-2 family members appears possible if not likely, but is not established. The issue is important for the development of antiapoptotic compounds for the treatment of this disease because of differential involvement of p53 in different mutant superoxide dismutase (SOD) mice. Most debated is the role of apoptosis in AD; this implies that little is known about potentially involved pathways. Moreover, there is a lack of suitable animal models for compound evaluation. Apoptosis or related phenomena are likely involved in secondary cell death in cerebral ischemia, TBI, and SCI. Most of the pertinent information comes from animal experiments, which have provided some evidence for prevention of cell death by antiapoptotic treatments, but little for functional benefit. Much remains to be done in this area to explore the potential of antiapoptotic drugs. There is a small number of antiapoptotic compounds in clinical development. With some of them, evidence for maintenance of functionality of the rescued neurons has been obtained in some animal models, and the fact that they made it to phase II studies in patients suggests that interference with physiological apoptosis is not an obligatory problem. The prospect that small antiapoptotic molecules will have an impact on the therapy of neurodegenerative diseases, and perhaps also of ischemia and trauma, is therefore judged cautiously positively.
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PMID:Prospects for antiapoptotic drug therapy of neurodegenerative diseases. 1265 69

BAK is a pro-apoptotic BCL-2 family protein that localizes to mitochondria. Here we evaluate the function of BAK in several mouse models of neuronal injury including neuronotropic Sindbis virus infection, Parkinson's disease, ischemia/stroke, and seizure. BAK promotes or inhibits neuronal death depending on the specific death stimulus, neuron subtype, and stage of postnatal development. BAK protects neurons from excitotoxicity and virus infection in the hippocampus. As mice mature, BAK is converted from anti- to pro-death function in virus-infected spinal cord neurons. In addition to regulating cell death, BAK also protects mice from kainate-induced seizures, suggesting a possible role in regulating synaptic activity. BAK can alter neurotransmitter release in a direction consistent with its protective effects on neurons and mice. These findings suggest that BAK inhibits cell death by modifying neuronal excitability.
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PMID:BAK alters neuronal excitability and can switch from anti- to pro-death function during postnatal development. 1268 95

The past few years have been marked by substantial progress in preclinical studies of therapeutic gene transfer for neurologic disease using viral-based vectors. In this article, the authors review the data regarding (1). treatment of focal neuronal degeneration, exemplified by Parkinson disease, ischemia, and trauma models; (2). treatment of global neurologic dysfunction, exemplified by the mucopolysaccharidoses and other storage diseases; (3). peripheral nervous system diseases including motor neuron disease and sensory neuropathies; and (4). the use of vectors expressing neurotransmitters to modulate functional neural activity in the treatment of pain. The results suggest that a number of different viral vectors may be appropriate for gene transfer to the central nervous system for specific disease processes, and that for the peripheral nervous system herpes simplex virus-based vectors appear to have special utility. The results of the first human gene therapy trials for neurologic disease, which are just now beginning, will be crucial in defining the next step in the development of this therapy.
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PMID:Therapeutic gene transfer to the nervous system using viral vectors. 1270 47

Stress proteins or in other words heat shock proteins form an ancient defense system of our cells. They are necessary to prevent the aggregation of damaged proteins and to help their refolding after stress. Stress protein-assisted remodeling of protein structure is an important step of many cellular processes, such as protein transport, signaling and protein degradation. Stress proteins have a key role in many diseases. Thus they 1. protect our cells against the deteriorating effects of ischemia/reperfusion in myocardiac infarcts or in stroke; 2. protect transplanted tissues and organs; 3. act against the multiple damage of chronic diseases such as diabetes, or neurodegenerative diseases (Alzheimer's and Parkinson's disease); 4. participate in the etiology of several autoimmune diseases; 5. their activation, and role in antigen presentation can be used as an anticancer-therapy; 6. stress proteins increase longevity, and lastly 7. stress proteins act as a buffer of phenotypically silent mutations and may contribute to the onset of "civilizational diseases" (cancer, atherosclerosis, diabetes, etc.). In this review the authors also summarize the existing stress protein-related pharmacological approaches to cure a large variety of diseases.
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PMID:[Stress proteins in medicine]. 1272 85

Adenosine is a ubiquitous autacoid that acts on four defined receptors, named A(1), A(2A), A(2B) and A(3). Although the biological activity of adenosine has been known for more than 70 years and the existence of specific receptors for more than 25 years, it is only now that the full potential for drug development is becoming clear. Among some of the conditions for which adenosine receptor-based therapy might be used are Parkinson's disease, hypoxia/ischemia, epilepsy, kidney disease and asthma.
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PMID:Adenosine receptors as targets for drug development. 1294 59

Diadenosine tetraphosphate (AP4A), an endogenous diadenosine polyphosphate, reduces ischemic injury in the heart. In this study, we report the potent and protective effects of AP4A in rodent models of stroke and Parkinson's disease. AP4A, given intracerebroventricularly before middle cerebral artery (MCA) ligation, reduced cerebral infarction size and enhanced locomotor activity in adult rats. The intravenous administration of AP4A also induced protection when given early after MCA ligation. AP4A suppressed terminal deoxynucleotidyl transferase-mediated biotinylated UTP nick end labeling (TUNEL) induced by hypoxia/reperfusion in primary cortical cultures, and reduced both ischemia-induced translocation of mitochondrial cytochrome c and the increase in cytoplasmic caspase-3 activity in vivo. The purinergic P2/P4 antagonist di-inosine pentaphosphate or P1-receptor antagonist sulfonylphenyl theophylline, but not the P2-receptor antagonist suramin, antagonized the effect of AP4A, suggesting that the observed protection is mediated through an anti-apoptotic mechanism and the activation of P1- and P4-purinergic receptors. AP4A also afforded protection from toxicity induced by unilateral medial forebrain bundle injection of 6-hydroxydopamine (6-OHDA). One month after lesioning, vehicle-treated rats exhibited amphetamine-induced rotation. Minimal tyrosine hydroxylase immunoreactivity was detected in the lesioned nigra or striatum. No KCl-induced dopamine release was found in the lesioned striatum. All of these indices of dopaminergic degeneration were attenuated by pretreatment with AP4A. In addition, AP4A reduced TUNEL in the lesioned nigra 2 d after 6-OHDA administration. Collectively, our data suggest that AP4A is protective against neuronal injuries induced by ischemia or 6-OHDA through the inhibition of apoptosis. We propose that AP4A may be a potentially useful target molecule in the therapy of stroke and Parkinson's disease.
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PMID:Diadenosine tetraphosphate protects against injuries induced by ischemia and 6-hydroxydopamine in rat brain. 1294 27

Minocycline has been shown previously to have beneficial effects against ischemia in rats as well as neuroprotective properties against excitotoxic damage in vitro, nigral cell loss via 6-hydroxydopamine, and to prolong the life-span of transgenic mouse models of Huntington's disease (HD) and amyotrophic lateral sclerosis (ALS). We investigated whether minocycline would protect against toxic effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a toxin that selectively destroys nigrostriatal dopaminergic (DA) neurons and produces a clinical state similar to Parkinson's disease (PD) in rodents and primates. We found that although minocycline inhibited microglial activation, it significantly exacerbated MPTP-induced damage to DA neurons. We present evidence suggesting that this effect may be due to inhibition of DA and 1-methyl-4-phenylpridium (MPP+) uptake into striatal vesicles.
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PMID:Minocycline enhances MPTP toxicity to dopaminergic neurons. 1451 57


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