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)

Pramipexole (SND 919; 2-amino-4,5,6,7-tetrahydro-6-propyl-amino-benzthiazole- dihydrochloride) was tested for its agonistic activity at pre- and postsynaptic dopamine (DA) receptors. L-Dihydroxyphenylalanine (L-dopa) accumulation in the rat striatum and limbic system and the alpha-methyltyrosine-induced reduction of DA were inhibited. Both effects were fully antagonized by haloperidol but not by the selective DA D1 receptor antagonist SCH 23390. Pramipexole decreased the levels of DA metabolites dose dependently, whereas striatal DA levels remained unchanged. In mice, pramipexole (0.001-1 mg/kg s.c.) reduced exploratory locomotor activity. In rats with unilateral striatal lesions, only weak ipsilateral rotation was produced by pramipexole at the highest dose. However, in rats with unilateral lesions of the medial forebrain bundle, pramipexole potently induced contralateral circling (ED50 0.026 mg/kg s.c.). In the N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) monkey model, pramipexole also had potent stimulatory effects. Finally, in haloperidol-sensitized monkeys, the substance did not elicit dyskinesia/dystonia when given alone, but rather inhibited those symptoms which had been induced by haloperidol (ED50 0.116 mg/kg i.m.). It is concluded that pramipexole has therapeutic potential for schizophrenic patients, as a result of its autoreceptor agonistic effects and its weak effects at normosensitive postsynaptic DA receptors. Furthermore, its potent stimulatory effects in DA-depleted animals suggest a possible use in the treatment of Parkinson's disease.
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PMID:Biochemical and pharmacological studies on pramipexole, a potent and selective dopamine D2 receptor agonist. 135 88

Pramipexole (PPX) is currently being evaluated for treatment of schizophrenia and Parkinson's disease. In studies with cloned subtypes of the dopamine (DA) D2 receptor subfamily, PPX has higher affinity for the D3 compared to the D2 and D4 subtypes; unlike 7-[3H]hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OH-DPAT), it does not bind to sigma sites. Receptor binding autoradiography with [3H]PPX (5 nM, 62 Ci/mmol) was used to evaluate the distribution of PPX binding sites within the rat brain. Consistent with its preference for D3-binding sites, the highest concentrations of [3H]PPX binding sites were found in the islets of Calleja (ICj), previously reported to contain D3 but not D2 or D4 mRNA. [3H]PPX binding was also high in other mesolimbic areas such as the nucleus accumbens (N. accum), olfactory tubercle, and amygdala. [3H]PPX binding was also high in caudate (Cd), although slightly less than in mesolimbic areas. Less [3H]PPX binding sites were found in ventral tegmental area (VTA) and substantia nigra, areas rich in cell bodies for DA neurons. Thus, although PPX most potently stimulates DA autoreceptors, PPX binding sites have their highest concentrations in projection areas containing both DA terminal and postsynaptic receptors. Because of PPX's preferential affinity for the D3 receptor subtype and its resultant high mesolimbic binding, it could have a unique therapeutic profile for treatment of psychiatric and/or neurological diseases.
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PMID:Rat brain binding sites for pramipexole, a clinically useful D3-preferring dopamine agonist. 750 Dec 68

We evaluated the efficacy, safety, tolerability, and pharmacokinetics of pramipexole, a novel dopamine D2 receptor agonist, in early Parkinson's disease (PD). The study design was a parallel, placebo-controlled trial using an ascending dose of 4.5 mg/day pramipexole maximum. All subjects received selegiline (10 mg/day) but were not treated with levodopa. Of the 55 subjects who received at least one dose of the study medication, all but one, in the placebo group, completed the trial, which was 9 weeks in duration. The primary efficacy endpoints were changes in scores from baseline to final measurement on the Unified Parkinson's Disease Rating Scale (UPDRS) Parts II and III. The pramipexole group had a significantly greater improvement (p = 0.002) than the placebo group on UPDRS Part II (Activities of Daily Living). The change in score from baseline to final measurement on UPDRS Part III (Motor Examination) was not significantly different (p = 0.10) between the pramipexole and placebo groups, although the trend favoured the pramipexole group. All subjects in both the pramipexole and the placebo groups experienced one or more episodes of asymptomatic orthostatic hypotension; there was no significant difference between the pramipexole and the placebo groups in the number of subjects experiencing symptomatic orthostatic hypotension. The adverse events profile of pramipexole was similar, in general, to that of other dopamine receptor agonists. Plasma pramipexole levels increased linearly with dose. Pramipexole appears to be promising agent in the treatment of early PD.
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PMID:Pramipexole in patients with early Parkinson's disease. 866 47

We evaluated the efficacy, safety and tolerability of a new dopamine D-2 receptor agonist, pramipexole [(S)-2-amino-4,5,6,7-tetrahydro-6-propylamino-benzathiazol-dihydro chloride], as adjunctive therapy in patients with advanced Parkinson's disease (PD). Twenty-four PD patients with motor fluctuations were treated in an 11 week prospective, single-blind parallel-group, placebo-controlled trial. The pramipexole treated group experienced a significant improvement in "off" time functioning as measured by the activities of daily living portion of the United Parkinson's Disease Rating Scale. In addition, the active treatment group was able to reduce total levodopa dose by 30% (p < 0.05). Pramipexole was well tolerated and the side effects reported were typical of other dopamine agonists. We conclude that pramipexole has antiparkinsonian effects which make it potentially useful in the treatment of motor fluctuations in PD.
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PMID:The use of pramipexole, a novel dopamine (DA) agonist, in advanced Parkinson's disease. 874 29

Pramipexole, an amino-benzathiazole [(S)-4,5,6,7-tetrahydro-N-6-propyl-2, 6-benzothiazolediamine dihydrochloride monohydrate] direct-acting dopamine receptor agonist effective in treating Parkinson's disease, bound selectively and with high affinity to dopamine D2-like receptors, with highest affinity at dopamine D3 receptors. Ergot dopamine receptor agonists (bromocriptine, lisuride, pergolide) bound to both dopamine and non-dopamine receptors. Although all agonists depressed dopamine neuron firing, only pramipexole and quinpirole completely silenced firing when administered in slowly-accumulating doses. High-dose pergolide, but not other ergots, completely suppressed firing when given by a prompt bolus i.v. injection, suggesting efficacy limitations may have involved receptor desensitization for pergolide, but not for bromocriptine and lisuride. We conclude that pramipexole differs from ergot dopamine receptor agonists currently used in the treatment of Parkinson's disease by virtue of its selectivity for dopamine receptors, its preferential affinity for the dopamine D3 receptor subtype, and its greater efficacy for stimulating dopamine receptors, as indicated in these electrophysiology assays.
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PMID:Inhibition of dopamine neuron firing by pramipexole, a dopamine D3 receptor-preferring agonist: comparison to other dopamine receptor agonists. 889 76

Pramipexole is a dopamine receptor agonist that has proved effective in the treatment of Parkinson's disease. The pharmacokinetic properties of pramipexole at steady-state concentrations were studied in 16 healthy men and women at four dose levels throughout the range recommended for Parkinson's patients. Plasma and urine samples collected within the four dose intervals were assayed for concentrations of pramipexole, using high-performance liquid chromatography. The total oral clearance for all participants was 419 mL/min. The mean volume of distribution and elimination half-life for all participants was 486 +/- 93.2 L and 12.9 +/- 3.27 hours. Concentrations of pramipexole were proportional to dose, although the drug's pharmacokinetic properties differed between men and women. The area under the concentration-time curve for each dose level was 35% to 43% greater in women, mainly because of a 24% to 27% lower oral clearance. The mean creatinine clearance in men and women was 112 +/- 12.8 mL/ min/1.73 m2 and 80.9 +/- 15.6 mL/min/1.73 m2, respectively. The renal clearance of pramipexole accounts for approximately 80% of oral clearance, and there was a significant correlation between renal and creatinine clearances. The influence of gender could not be distinguished from the influence of age and the resulting reduced creatinine clearance, but the measurement of pharmacokinetic properties produced linear results in both men and women.
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PMID:Steady-state pharmacokinetic properties of pramipexole in healthy volunteers. 920 59

We compared the efficacy, safety, an tolerability of pramipexole, an aminobenzathiazol-derived dopamine agonist with novel properties, with those of placebo in advanced PD patients with motor fluctuations under levodopa treatment. Pramipexole improved motor function of patients during "on" and "off" periods, decreased the time spent in "off" periods, reduced the severity of "off" periods, decreased disability and PD severity during "on" and "off" periods, as assessed by the Unified Parkinson Disease Rating Scale, and permitted a reduction in levodopa dosage. Adverse effects related to the central nervous system were similar to those reported with other dopamine agonists, and the gastrointestinal and cardiovascular tolerability of the compound was satisfactory.
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PMID:Clinical evaluation of pramipexole in advanced Parkinson's disease: results of a double-blind, placebo-controlled, parallel-group study. 922 85

A total of 335 patients with early Parkinson's disease (PD) were enrolled in a multicenter, randomized, double-blind trial designed to assess the efficacy and safety of pramipexole. Entry was restricted to patients with idiopathic PD who were not receiving levodopa. Pramipexole was administered according to an ascending dose schedule up to 4.5 mg/d. During the 7-week dose-escalation phase, each subject was titrated to his or her maximally tolerated dose of study medication. This was followed by a 24-week period of maintenance therapy. The mean daily dose during the maintenance period was 3.8 mg. Pramipexole significantly reduced the severity of PD symptoms and signs compared with placebo, as measured by decreases in parts II (Activities of Daily Living) and III (Motor Examination) of the Unified Parkinson's Disease Rating Scale at week 24 compared with baseline (p < or = 0.0001). Differences between the active drug and placebo groups emerged at week 3 (1.5 mg/d) in the ascending-dose interval and persisted throughout the maintenance phase (p < or = 0.0001). The majority of patients completed the study (pramipexole 83%, placebo 80%). In the assessment of adverse events, nausea, insomnia, constipation, somnolence, and visual hallucinations occurred more frequently in the pramipexole treatment group compared with placebo patients. No clinically significant changes were noted in blood pressure or pulse rate. Overall, these results indicate that pramipexole is safe and effective in the treatment of early PD.
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PMID:Efficacy of pramipexole, a novel dopamine agonist, as monotherapy in mild to moderate Parkinson's disease. The Pramipexole Study Group. 930 31

Pramipexole is a new, selective, nonergoline dopamine agonist that acts on D2 and preferentially on D3 dopamine receptors. Phase II and III clinical trials have shown this drug to be useful in treating both early and advanced Parkinson's disease (PD) patients. A double-blind, randomized, multicenter study was performed to compare the safety, tolerance, and efficacy of pramipexole versus placebo in patients with advanced PD with motor fluctuations. A bromocriptine treatment group was included to enable comparisons between bromocriptine and placebo groups, but the study was not powered to show statistical differences between the active treatment groups. The study included 247 patients with "wearing off." Patients were Hoehn and Yahr stages II to IV during "on" times. The trial included three phases: dose escalation, 6 months' maintenance, and dose reduction. The primary end points were the Unified Parkinson's Disease Rating Scale (UPDRS) parts II and III. Up to 4.5 mg per day of pramipexole and 30 mg per day of bromocriptine were used. The results of the study showed that the UPDRS part II improved by 26.7% for pramipexole (p = 0.0002) and 14% for bromocriptine (p = 0.02) versus 4.8% for placebo. The UPDRS part III showed improvements of 34% for pramipexole (p = 0.0006) and 23.8% for bromocriptine (p = 0.01) versus 5.7% for placebo. There were no major differences in safety data. In the active treatment groups there were more reports of dyskinesia and nausea compared with placebo. In regard to comparison of the Global Clinical Assessment of Efficacy between active treatment groups, there was a trend to significance (p = 0.056) in favor of pramipexole. We conclude that pramipexole-treated patients with advanced PD improved significantly more than placebo for both primary end points.
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PMID:Double-blind comparison of pramipexole and bromocriptine treatment with placebo in advanced Parkinson's disease. International Pramipexole-Bromocriptine Study Group. 933 90

Pramipexole is a clinically effective nonergot dopamine agonist. Pramipexole's receptor interactions differ from ergot agonists in several ways. First, it has high selectivity for interacting with dopamine D2 subfamily receptors (D2, D3, and D4 receptor subtypes) and has little interaction with adrenergic or serotonergic receptors. Second, within the D2 subfamily, it has preferential affinity for the D3 receptor subtype, which, according to preclinical studies, could contribute additional efficacy for treatment of both motor and psychiatric syndromes in Parkinson's disease. Third, it has full intrinsic activity at dopamine D2 subfamily receptors. In addition to pramipexole's unusual receptor profile, whole-animal and cell culture studies suggest that pramipexole might provide neuroprotective effects through depression of dopamine metabolism, antioxidant effects, and stimulation of trophic activity. Pramipexole's demonstrated clinical efficacy for successful treatment in early disease for several years in the absence of L-dopa and as adjunctive therapy with L-dopa in late disease suggests a potential new paradigm for treatment of Parkinson's disease whereby new patients are initiated with pramipexole therapy and L-dopa is added only as necessary.
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PMID:Pharmacology of pramipexole, a dopamine D3-preferring agonist useful in treating Parkinson's disease. 961 5


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