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)

These studies characterise the pharmacology of ropinirole, a selective D-2 agonist. High-affinity human caudate binding revealed a Ki for D2 receptors of 2.9 x 10(-8) M with no affinity for D1 at 10(-4) M in the rat. Ropinirole was weakly active at alpha 2-adrenoceptors and 5-HT2 receptors but inactive at 5-HT1, benzodiazepine and gamma-aminobutyric acid receptors or alpha 1 and beta-adrenoceptors. In rodents, ropinirole, like apomorphine, caused biphasic spontaneous locomotor activity and contralateral circling in 6-OHDA-lesioned mice with no tolerance to the latter after 14 days treatment. Amphetamine caused ipsilateral responses in the lesioned mice. Ropinirole did not cause marked stereotypies. In marmosets ropinirole (0.05-1.0 mg/kg SC or 0.1 mg/kg PO) reversed all motor and behavioural deficits induced by MPTP. This response started 10-20 minutes after dosing, and exceeded 2 hours. No tolerance was seen following chronic b.i.d. treatment. Similar results were obtained with 1-dopa plus benserazide; however, 1-dopa always caused emesis, whereas beneficial effects were shown with ropinirole in the absence of this side effect. These results support the continued clinical assessment of ropinirole for the treatment of Parkinson's disease.
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PMID:Preclinical pharmacology of ropinirole (SK&F 101468-A) a novel dopamine D2 agonist. 167 48

The long-term effect of the parkinsonism inducing neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on pre- and postsynaptic structures of the nigrostriatal and mesolimbic dopamine (DA) system in adult C57BL/6 mice (2 x 40 mg/kg s.c.) was investigated using neurochemical and behavioral methods. It was found that MPTP induced a severe depletion of striatal DA levels (-80%) that persists for 4 weeks after treatment, with less severe effects in nucleus accumbens (-36%) and the olfactory tubercle (-52%). These depletions are associated with decreased tyrosine hydroxylase (TH) activity as determined in vivo and increased turnover of DA. MPTP treatment did not induce any change in the DA2-receptor as determined by [3H]spiperone binding or by two different behavioral tests, i.e. apomorphine-induced climbing and apomorphine-induced stereotypies. No significant weight loss during 4 weeks after MPTP was found. The spontaneous motor activity in these mice was profoundly and persistently depressed (-66%) as a result of the MPTP-induced DA denervation and the motor deficit was completely reversed by L-DOPA treatment. We suggest that MPTP-treated C57BL/6 mice may serve as a suitable model for Parkinson's disease.
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PMID:Chronic neurochemical and behavioral changes in MPTP-lesioned C57BL/6 mice: a model for Parkinson's disease. 227 21

From the data discussed in this review it appears that GABA receptor agonists exhibit a variety of actions in the central nervous system, some of which are therapeutically useful (Table V). GABA receptor agonists, by changing the firing rate of the corresponding neurons accelerate noradrenaline turnover without changes in postsynaptic receptor density and diminish serotonin liberation with an up-regulation of 5HT2 receptors. These effects differ from those of tricyclic antidepressants which primarily block monoamine re-uptake and cause down-regulation of beta-adrenergic and 5HT2 receptors. The GABA receptor agonist progabide has been shown to exert an antidepressant action which is indistinguishable from that of imipramine in patients with major affective disorders. The fact that: (a) GABA receptor agonists and tricyclic antidepressants affect noradrenergic and serotonergic transmission differently; and (b) tricyclic antidepressants alter GABA-related parameters challenges the classical monoamine hypothesis of depression and suggests that GABA-mediated mechanisms play a role in mood disorders. Decreases in cellular excitability produced by GABAergic stimulation leads to control of seizures in practically all animal models of epilepsy. GABA receptor agonists have a wide spectrum as they antagonize not only seizures which are dependent on decreased GABA synaptic activity but also convulsant states which are apparently independent of alterations in GABA-mediated events. These results in animals are confirmed in a wide range of human epileptic syndromes. GABA receptor agonists decrease dopamine turnover in the basal ganglia and antagonize neuroleptic-induced increase in dopamine release. On repeated treatment, progabide prevents or reverses the neuroleptic-induced up-regulation of dopamine receptors in the rat striatum and antagonizes the concomitant supersensitivity to dopaminomimetics. Behaviorally, GABA receptor agonists diminish the stereotypies induced by apomorphine or L-DOPA suggesting that GABAergic stimulation results also in an antidopaminergic action which is exerted beyond the dopamine synapse. These effects of GABA receptor agonists may represent the basis of the antidyskinetic action of these compounds which, however, remains to be fully confirmed. GABA receptor agonists reduce striatal acetylcholine turnover, an effect which occurs at doses much lower than those which affect dopamine neurons. Since hyperactivity of cholinergic neurons plays a determinant role in the pathogenesis of some parkinsonian symptoms, it is conceivable that GABAergic stimulation is effective in ameliorating Parkinson's disease.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:GABA receptor agonists: pharmacological spectrum and therapeutic actions. 298 90

Terguride, an analogue of lisuride, decreased locomotor activity, produced cataplexy, and blocked apomorphine-induced stereotypic behavior. It did not induce stereotypies in rodents or emesis in dogs. However, in rats with unilateral 6-hydroxydopamine lesions of the substantia nigra, terguride produced contralateral rotation. Terguride bound to D-2 striatal dopamine receptors. Terguride has both agonist and antagonist actions at striatal dopamine receptors, but chronic administration did not produce behavioral supersensitivity. These pharmacologic properties differ from those of other antiparkinsonian agents; terguride may be effective for the chronic treatment of Parkinson's disease.
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PMID:Terguride, a mixed dopamine agonist-antagonist, in animal models of Parkinson's disease. 356 89

This article focuses on the current knowledge about movement disorders associated with alcohol and drug abuse. Chronic alcohol use can produce a wide spectrum of movement disorders including tremor, withdrawal parkinsonism and dyskinesias, cerebellar ataxia, and asterixis. MPTP, a neurotoxin first reported to cause parkinsonism in a group of drug abusers, has provided important insights into the pathogenesis of Parkinson's disease. There is a growing body of literature providing evidence that dyskinesias such as tics and dystonia may be precipitated or exacerbated by cocaine. Amphetamines have been implicated in the production of stereotypies and exacerbation of tics.
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PMID:Movement disorders. 837 47

Sprague-Dawley rats received a unilateral injection of 6-hydroxydopamine (6-OHDA) into the striatum and were treated daily for 6 weeks with increasing doses of monoamine oxidase type B inhibitor rasagiline [R(+)-N-propargyl-1-aminoindane] or saline (controls). Both doses of rasagiline markedly increased the survival of dopaminergic neurons in the lesioned substantia nigra, compared to controls (+97% and +119%, respectively). Treatment with the lower dose of rasagiline also abolished the motor stereotypies associated with nigrostriatal lesion. Our study supports the neuroprotective potential of chronic rasagiline administration in an experimental model of Parkinson's disease (PD).
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PMID:Neuroprotective effect of rasagiline in a rodent model of Parkinson's disease. 1514 71

SL25.1131 [3(S),3a(S)-3-methoxymethyl-7-[4,4,4-trifluorobutoxy]-3,3a,4,5-tetrahydro-1,3-oxazolo[3,4-a]quinolin-1-one] is a new, nonselective, and reversible monoamine oxidase (MAO) inhibitor, belonging to a oxazoloquinolinone series. In vitro studies showed that SL25.1131 inhibits rat brain MAO-A and MAO-B with IC50 values of 6.7 and 16.8 nM and substrate-dependent Ki values of 3.3 and 4.2 nM, respectively. In ex vivo conditions, the oral administration of SL25.1131 induced a dose-dependent inhibition of MAO-A and MAO-B activities in the rat brain with ED50 values of 0.67 and 0.52 mg/kg, respectively. In the rat brain, duodenum, and liver, the inhibition of MAO-A and MAO-B by SL25.1131 (3.5 mg/kg p.o.) was reversible, and the recovery of MAO-A and MAO-B activities was complete 16 h after administration. SL25.1131 (3.5 mg/kg p.o.) increased tissue levels of dopamine (DA), norepinephrine, and 5-hydroxytryptamine and decreased levels of their deaminated metabolites 3,4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindolacetic acid. In mice, SL25.1131 induced a dose-dependent potentiation of 5-hydroxytryptophan-induced tremors and phenylethylamine-induced stereotypies with ED50 values of 0.60 and 2.8 mg/kg p.o., respectively. SL25.1131 was able to reestablish normal striatal dopaminergic tone and locomotor activity in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-lesioned mice. In addition, when coadministered with L-DOPA, SL25.1131 increased the available DA in the striatum and the duration of L-DOPA-induced hyperactivity. The duration of the effect of L-DOPA on circling behavior in 6-hydroxydopamine-lesioned rats was also increased. The neurochemical profile of SL25.1131 demonstrates that this compound is a mixed, potent, and reversible MAO-A/B inhibitor in vitro, in vivo, and ex vivo. SL25.1131 has therapeutic potential as a symptomatic treatment during the early phase of Parkinson's disease and as an adjunct to L-DOPA therapy during the early and late phases of the disease.
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PMID:SL25.1131 [3(S),3a(S)-3-methoxymethyl-7-[4,4,4-trifluorobutoxy]-3,3a,4,5-tetrahydro-1,3-oxazolo[3,4-a]quinolin-1-one], a new, reversible, and mixed inhibitor of monoamine oxidase-A and monoamine oxidase-B: biochemical and behavioral profile. 1517 94

Overexpression of alpha-synuclein causes familial Parkinson's disease and abnormal aggregates of the protein are present in sporadic cases of the disease. We have examined the behavioral effects of direct and indirect dopaminergic agonists in transgenic mice expressing human alpha-synuclein under the Thy-1 promoter (Thy1-aSyn, alpha-synuclein overexpressor), which exhibit progressive impairments in behavioral tests sensitive to nigrostriatal dopamine dysfunction. Male Thy1-aSyn and wild-type mice received vehicle, benserazide/L-DOPA (25 mg/kg, i.p.), high (2 mg/kg, s.c.) and low doses (0.125, 0.25, 0.5 mg/kg, s.c.) of apomorphine, and amphetamine (5 mg/kg, i.p.), beginning at 3 months of age, and were tested on the challenging beam, spontaneous activity, pole test, and gait. l-DOPA had a paradoxical effect and worsened the deficits in Thy1-aSyn mice compared with controls, whereas the high dose of apomorphine only produced few deficits above those already present in Thy1-aSyn. In contrast to wild-type mice, Thy1-aSyn mice did not show amphetamine-induced stereotypies. The results indicate that chronic overexpression of alpha-synuclein led to abnormal pharmacological responses in mice.
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PMID:Behavioral effects of dopaminergic agonists in transgenic mice overexpressing human wildtype alpha-synuclein. 1693 9

Investigation of the pathophysiology of psychosis in Parkinson's disease (PD), as well as the assessment of potential novel therapeutics, has been limited by the lack of a well-validated animal model. MPTP-lesioned primates exhibit abnormal behaviors that are distinct from dyskinesia and parkinsonism and may represent behavioral correlates of neural processes related to psychosis in PD. Here we assess four types of behavior--agitation, hallucinatory-like responses to nonapparent stimuli, obsessive grooming, and stereotypies that are termed "psychosis-like"--and define their pharmacology using a psychosis-like behavior rating scale. By assessing the actions of drugs known to enhance or attenuate psychosis in PD patients, we find that the pharmacology of these behaviors recapitulates, in several respects, the pharmacology of psychosis in PD. Thus, levodopa and apomorphine elicited psychosis-like behaviors. Amantadine significantly decreased levodopa-induced dyskinesia but exacerbated psychosis-like behaviors. Haloperidol reduced psychosis-like behaviors but at the expense of increased parkinsonian disability while the atypical neuroleptics clozapine and quetiapine reduced psychosis-like behaviors without significant effect on parkinsonian disability. The response of different components of the psychotomimetic behavior suggested the involvement of both dopaminergic and nondopaminergic mechanisms in their expression.
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PMID:Pharmacological characterization of psychosis-like behavior in the MPTP-lesioned nonhuman primate model of Parkinson's disease. 1696 Aug 62

Parkinson's disease, the most common hypokinetic movement disorder, has received much attention from the clinical and scientific community, but there has been a relative paucity of comprehensive reviews of hyperkinetic disorders, even though they are equally or even more disabling. Hyperkinetic movement disorders include tremors, dystonia, chorea, tics, myoclonus, stereotypies, restless legs syndrome, and various other disorders with abnormal involuntary movements. Substantial progress has been made in the understanding of the role of the basal ganglia in the pathophysiology of these hyperkinesia disorders and in motor control, muscle tone, posture, and cognitive processes. Although therapies that target pathogenesis are still lacking, effective management of hyperkinetic movement disorders demands that physicians are knowledgeable about current and novel pharmacological and surgical approaches. In addition to tetrabenazine, a monoamine-depleting drug, new formulations of botulinum toxin are being increasingly used in the treatment of these movement disorders. Finally, success with surgical approaches, particularly deep brain stimulation in patients with Parkinson's disease who have levodopa-induced dyskinesias, has been extended to the treatment of many hyperkinetic movement disorders.
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PMID:Treatment of hyperkinetic movement disorders. 1967 76


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