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)

alpha-Dihydroergocryptine (alpha-DHEC) is a well known dopaminergic agent successfully employed in the treatment of Parkinson's disease. alpha-DHEC showed a neuroprotective activity against total cerebral ischemia induced by MgCl2 in mice and histocytic anoxia by NaCN in mice and rats. Moreover the drug promoted the recovery of locomotor activity in rats after cerebral ischemic damage and protected mice against convulsions induced by intracerebroventricular injections of NMDA and glutamate. alpha-DHEC showed a protective activity on neuronal degeneration induced by MPTP in monkeys, as evaluated through animal's behaviour and morphological-cytochemical changes in the substantia nigra, suggesting a preservative effect on neuronal morphology and brain architecture. In the MPTP-treated monkeys, the alpha-DHEC administration induced a restoration of the unstimulated MDA values to control levels. The neuroprotective activity of alpha-DHEC is related to its peculiar activity on antioxidative enzymes of GSH system and to reduction of lipid-peroxide-induced cellular degeneration.
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PMID:Neuroprotective activity of alpha-dihydroergocryptine in animal models. 874 39

The repeated administration of nicotine at small doses, which do not produce whole body tremor or convulsion, causes tremor only in the tail (tail-tremor) of rats. The tremor is accompanied by locomotor hyperactivity without rigidity and immobility of the whole body, suggesting that the nicotine-induced tail-tremor model is useful for studying the mechanism underlying tremor associated with movement. The tail-tremor induced by nicotine was suppressed by mecamylamine, a nicotinic antagonist, but not by atropine or scopolamine, muscalinic antagonists. Moreover, the tail-tremor was suppressed by the beta-blockers propranolol and pindolol, as well as the benzodiazepines diazepam and clonazepam. Tremor at rest is observed only in Parkinson's disease, which is improved with anti-muscalinic drugs. Essential tremor is one of the typical tremors connected with movement (postural and kinetic tremor) and is improved with beta-blocker. These findings and results suggest that nicotine-induced tail-tremor is useful for the study of essential tremor in animal models.
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PMID:[Assessment of anti-tremorogenic drugs--nicotine-induced tail-tremor model]. 927 37

Selegiline (SEL) is a selective, irreversible inhibitor of MAO-B, used in the treatment of Parkinson's disease, either alone or as an adjunct to L-DOPA. Selegiline hydrochloride (HCl) undergoes significant first-pass metabolism following oral administration. Transdermal delivery avoids the first-pass effect and provides greater and more prolonged levels of unchanged SEL and reduced levels of metabolites (N-desmethylselegiline (DES), L-amphetamine (AMP), and L-methamphetamine (MET) compared to the oral regimen. An integrated pharmacokinetic-metabolic model which predicts plasma concentrations of SEL and metabolites following a single 24 h application of a selegiline transdermal system (STS) is proposed. The model is based on the metabolic conversion of SEL to DES and MET and subsequently to AMP. The input function is described by a zero-order constant for the delivery of SEL from the STS system based on in vitro studies of penetration of SEL across human skin. The elimination-non-metabolic constants for each analyte account for the urinary elimination. Plasma concentration data from a pilot pharmacokinetic study in which six healthy male volunteers were administered single 24 h applications of a 1.8 mg cm2, 10 cm2 STS were used to examine this model. The coefficient of determination was 0.98 and model selection criterion was 3.4 for mean data fits, supporting the goodness of fit of the model. The pharmacokinetic parameters obtained by non-compartmental analysis were comparable to those predicted by a compartmental model. The model also predicted urinary recoveries for AMP and MET and negligible recovery for SEL and DES consistent with recent studies with the STS in which urine was collected. The metabolic conversion constant from SEL to DES was significantly lower than the conversion constant from SEL to MET, indicating that metabolism of SEL is primarily driven towards MET following transdermal administration. The metabolic conversion from MET to AMP was less than the conversion from DES to AMP. This simultaneous prediction of the SEL and metabolites is essential as the metabolic ratios have been linked to the neuroprotective effects of SEL. These findings support the proposed regional delivery advantage attributed to the transdermal route compared to the conventional therapy with the oral tablet. Future model applications may also help identify significant covariates (i.e. age, gender, and disease state) in upcoming clinical trials.
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PMID:Integrated pharmacokinetic and metabolic modeling of selegiline and metabolites after transdermal administration. 933 Jul 78

New A2A adenosine receptor antagonists in the series of pyrazolo[4, 3-e]-1,2,4-triazolo[1,5-c]pyrimidines, bearing oxygenated substituents on the phenylalkyl chains on the 7-position, have been synthesized. The compounds were tested in binding and functional assays to evaluate affinity, potency, and selectivity for rat A2A compared to rat A1 and human A3 receptor subtypes. The most interesting compounds (5d,e,h) were tested also in binding to human A1 and A2A adenosine receptors. They showed very good affinity (Ki = 0.94 nM for compound 5h) and interesting selectivity with respect to both rA1 and hA3 (compound 5h: rA1/rA2A = 787, hA3/rA2A > 10 000). These important findings make this new series of compounds the first really selective for A2A adenosine receptors. Thermodynamic parameters were evaluated; all the tested compounds displayed an enthalpy-driven binding as expected for antagonists. Moreover, compound 5h showed a negative entropy value. The highly negative enthalpic and entropic contributions could mean that 5h fits very well in the binding site where, probably, an electrostatic interaction is present associated to a scarce solvent reorganization around the receptor binding site. These compounds deserve to be further developed to assess their potential for treatment of neurodegenerative disorders such as Parkinson's disease.
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PMID:Design, synthesis, and biological evaluation of a second generation of pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidines as potent and selective A2A adenosine receptor antagonists. 962 54

Increased GABAergic neurotransmission of the basal ganglia output nuclei projecting to the motor thalamus is thought to contribute to the pathophysiology of Parkinson's disease. We investigated the functional role of thalamic GABA(B) receptors in a rodent model of Parkinson's disease. First, we examined the effects of blockade of GABA(B) receptors in the ventromedial thalamic nucleus of rats with a unilateral 6-OHDA lesion of the substantia nigra on locomotor activity. In addition we studied the expression of GABA(B) receptor mRNA in the basal ganglia and thalamus using in situ hybridisation. Unilateral microinjections of the GABA(B) receptor antagonist 2-hydroxysaclofen into the ventromedial thalamic nucleus ipsilateral to the nigrostriatal lesion induced contralateral rotations in a dose-dependent manner. However, microinjection of antagonists with higher affinity for the GABA(B) receptor SCH 50911, CGP 56433 and CGP 55845 did not result in rotational behaviour, but did induce convulsions at higher doses. GABA(B) receptor mRNA expression was found throughout the basal ganglia and thalamus, including the ventromedial thalamic nucleus. No statistically significant differences in GABA(B) mRNA expression were observed in the ventromedial thalamic nucleus following a unilateral 6-OHDA lesion of the substantia nigra. These results make it improbable that thalamocortical GABA(B) receptors play an important role in the pathophysiology of parkinsonism. Therefore, GABA(B) receptors do not appear to be a promising target for novel antiparkinsonian drugs.
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PMID:Functional characterization and expression of thalamic GABA(B) receptors in a rodent model of Parkinson's disease. 1058 84

The neurotensin receptor 1 (NTR1) subtype belongs to the family of G protein-coupled receptors and mediates most of the known effects of the neuropeptide including modulation of central dopaminergic transmission. This suggested that nonpeptide agonist mimetics acting at the NTR1 might be helpful in the treatment of Parkinson's disease and schizophrenia. Here, we attempted to define the molecular interactions between neurotensin-(8-13), the pharmacophore of neurotensin, and the rat NTR1. Mutagenesis of the NTR1 identified residues that interact with neurotensin. Structure-activity studies with neurotensin-(8-13) analogs identified the peptide residues that interact with the mutated amino acids in the receptor. By taking these data into account, computer-assisted modeling techniques were used to build a tridimensional model of the neurotensin-(8-13)-binding site in which the N-terminal tetrapeptide of neurotensin-(8-13) fits in the third extracellular loop and the C-terminal dipeptide binds to residues at the junction between the extracellular and transmembrane domains of the receptor. Interestingly, the agonist binding site lies on top of the previously described NTR1-binding site for the nonpeptide neurotensin antagonist SR 48692. Our data provide a basis for understanding at the molecular level the agonist and antagonist binding modes and may help design nonpeptide agonist mimetics of the NTR1.
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PMID:Identification of residues involved in neurotensin binding and modeling of the agonist binding site in neurotensin receptor 1. 1061 22

The aim of the present study was to evaluate the effectiveness of the Kampo medication kamishoyo-san against tremor due to antipsychotic-induced parkinsonism. Kami-shoyo-san consists of several medicinal herbs that are known in traditional Chinese medicine to be effective in treating Parkinson's disease and convulsions. We gave kami-shoyo-san to eight patients at Higashiowari National Hospital who were exhibiting tremor, a symptom of antipsychotic-induced parkinsonism. The tremor was evaluated on a five-point scale before and after the administration of kamishoyo-san, and the findings were compared statistically. The results showed a stastistically significant reduction in the tremor after the administration of kami-shoyo-san (P<0.01), with 62.5% of patients showing an improvement of one point or more. The tremor did not worsen in any of the patients, and none complained of side-effects. Thus, kami-shoyo-san appears to be effective against the tremor from parkinsonism. Kami-shoyo-san consists of 10 medicinal herbs, including Radix Bulpleuri, Radix Paeoniae, Radix Angelicae Sinensis, and Radix Glycyrrhizae, which are effective in treating disturbances in muscular movement according to TCM theory. Of the 10 herbs contained in kami-shoyo-san, we believe the abovementioned ones are particularly effective in helping to reduce the tremor associated with parkinsonism.
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PMID:Effectiveness of the Kampo kami-shoyo-san (TJ-24) for tremor of antipsychotic-induced parkinsonism. 1104 9

L-Deprenyl (Selegeline) introduced for use in parkinson's disease, is implicated to show beneficial effects in epilepsy, alzheimer's disease, cognition, depression and other age related neurological diseases. In this study, we investigated the CNS effects of L-deprenyl with special reference to epilepsy, anxiety and cognition and memory in mice. L-deprenyl (10, 20 and 40 mg/kg) showed a significant anticonvulsant activity against pentylenetetrazole (PTZ)-induced convulsions. Combination of L-deprenyl (10 mg/kg) with the sub-protective dose of diazepam (1 mg/kg) showed potentiation of the anticonvulsant effect. In the maximal-electroshock (MES)-induced convulsions, L-deprenyl (10 mg/kg) significantly delayed the onset and decreased the duration of extensor phase. Its combination with the lower dose of phenytoin (10 mg/kg) showed potentiation in response compared to the per se effect of both the drugs. However, L-deprenyl did not show any protective effect in lithium-pilocarpine induced status epilepticus. Acute treatment with L-deprenyl had no effect on learning and memory. In chronic treatment, L-deprenyl per se showed no effect on learning and memory but did improve the condition in mice with scopolamine induced memory deficit. L-Deprenyl per se was anxiogenic though in combination with diazepam (1 mg/kg) it potentiated the antianxiety effect of the latter. The above observations suggest that in epilepsy, L-deprenyl might be acting partially by influencing the GABAA/benzodiazepine mechanism in the brain (similar to diazepam and phenytoin), and in cognition enhancing effect, the cholinergic system might be playing a role. Thus, L-deprenyl could prove to be an adjuvant in the antiepileptic therapy and beneficial in dementia associated with epilepsy.
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PMID:Studies on anticonvulsant actions of L-deprenyl. 1121 8

We report a 68-year-old woman who developed progressive dementia and parkinsonism. She was well until 1990 when she was 58 years of age. She started to show memory loss. Four years later, she developed difficulty in dressing and behavioral problems such as eating rice with her hands, going out of her house without purposes, and difficulty in finding the rest room in her house. She was admitted to the neurology service of Hatsuishi Hospital on January 19, 1996, when she was 64 years of the age. On admission, she was alert but markedly demented. The score of Hansegawa Dementia Scale was 0/30. She was unable to make any coherent conversation. She appeared to have dressing apraxia but did not appear to have aphasia. Cranial nerves were intact. She walked in small steps with stooped posture. She did not have motor weakness but she showed plastic rigidity in all four limbs. No tremor or ataxia was noted. Deep tendon reflexes were within normal limits but the plantar response was extensor bilaterally. She continued to deteriorate after admission. In May of 1998, she started to fall. In June of 1998, she had a generalized convulsion. In January of 1999, she became unable to take foods orally and a gastrostomy was placed. She expired on May 29, 1990. She was discussed in a neurological CPC and the chief discussant arrived at the conclusion that the patient had Alzheimer's disease. The question was whether her parkinsonism was a part of her Alzheimer's disease or she had an additional disease to explain her parkinsonism. Post-mortem examination revealed moderate to marked atrophy of the frontal and the temporal lobes as well as in the limbic areas with dilatation of the lateral ventricles. Marked neuronal loss was noted in the CA 1 to the subiculum region with gliosis. Neurofibrillary tangles were seen in the remaining neurons. Neuropil threads were seen by Gallyas-Braak staining. Similar changes were seen in the parahippocampal gyrus and in the entorhinal cortex. Senile plaques were seen in the insular cortex and in other cortical areas. Cortical type Lewy bodies were seen in the cingulate cortex. The Meynert nucleus showed marked neuronal loss and gliosis. The substantia nigra and the locus coeruleus showed moderate loss of pigmented neurons. Lewy bodies were seen in these regions. The dorsal motor nucleus of the vagal nerve was retained, however, one Lewy body was observed. Pathologic diagnosis was Alzheimer's disease plus Parkinson's disease. It is an interesting question whether or not her parkinsonism was due to nigral lesion or frontal lesions. It is known that parkinsonism may complicate in advanced Alzheimer's disease not necessarily due to nigral lesion. On the other hand, in incidental Lewy body disease, the substantia nigra shows mild Parkinson's disease-like change without clinical parkinsonism. This patient appeared to have been a true complication of Alzheimer's disease and Parkinson's disease.
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PMID:[A 68-year-old woman with dementia and parkinsonism]. 1188 67

There is little debate that deep brain stimulation (DBS) has been an effective tool in the treatment of Parkinson's disease as well as other movement disorders. There remains however, considerable debate concerning the mechanism(s) underlying its beneficial effect. The comparable effect of stimulation to ablation in the thalamus on tremor, and in the subthalamic nucleus (STN) and internal segment of the globus pallidus (GPi) on the motor signs associated with PD, have led many investigators to conclude that DBS acts to suppress neuronal activity, decreasing output from the stimulated site. There are, however, data that do not support this argument. Microdialysis studies in GPi showed increased levels of glutamate during STN stimulation, suggesting activation of glutamatergic output from the STN to the GPi. Studies in parkinsonian primates have demonstrated increased mean discharge rates of neurons in GPi during chronic stimulation in STN, and GPi stimulation in humans has been associated with a suppression of neuronal activity in the thalamus. Contrary to what one would expect if stimulation inhibits output from the stimulated structure, stimulation in GPe has been demonstrated to improve bradykinesia. Although arguments for increased output from the stimulated structure seem to conflict with the hypothesis that stimulation acts to inhibit neuronal activity, it is possible to explain these observations through a common mechanism, e.g. activation of fiber pathways. Based on this mechanism, the effect of stimulation on cellular activity in the stimulated site would be increased or decreased dependent on the neurotransmitter of the afferent fibers projecting to that site. However, in addition to activation of afferent fibers, projection axons from neurons in the stimulated structure, also readily excitable by electrical stimulation, would also be tonically activated and discharge independently of the soma, thereby increasing output from the structure during extracellular stimulation. Thus, although high frequency stimulation may inhibit neurons via activation of inhibitory afferents, the output from that structure may be increased as the result of activation of axonal elements leaving the target structure. This hypothesis would explain the present experimental results, is consistent with excitability profiles of neuronal elements based on their biophysical properties, and fits with more recent models emphasizing the role of altered patterns of neuronal activity in the development of hypokinetic and hyperkinetic movement disorders.
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PMID:Mechanisms of deep brain stimulation: excitation or inhibition. 1194 56


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