We investigated in an open, explanatory study a total of 24 patients meeting DSM-III-R criteria for schizophrenia. Eighteen patients were treated for at least 4 weeks with a fixed dose of orally ...administered haloperidol for at least 4 weeks (mean daily dosage ranging from 0.07 to 0.35 mg/kg b.w.), and 6 patients received haloperidol decanoate with a fixed dose for at least 4 months (dosage range 50-150 mg/4 weeks; calculated mean daily dosage ranging from 0.02 to 0.09 mg/kg b.w.). One week after injection of haloperidol decanoate, the single photon emission computed tomography examination was performed. Our data suggest that D@@d2@-dopamine-receptor occupancy of 50 mg/4 weeks haloperidol decanoate 1 week after injection corresponds to an oral dose of 4.5 mg/day haloperidol.
Parkinson's disease (PD) is associated with neurodegeneration of dopaminergic neurons and an accompanying neuroinflammatory process in the substantia nigra (SN). The cholinergic anti-inflammatory ...signalling pathway allows the autonomic nervous system to modulate immunologic stimuli and inflammatory processes. A major component of this pathway is the α7 nicotinic acetylcholine receptor (α7 nACh receptor), which is expressed on immune cells such as microglia.
To determine the role of this cholinergic anti-inflammatory signalling pathway, we investigated the effects of the selective α7 nACh agonist PNU-282987 and of the non-competitive nACh antagonist mecamylamine on microglia-induced neuroinflammation and toxin-induced degeneration of dopaminergic neurons in a mouse model of PD.
PNU-282987, mecamylamine or placebo administration was started one day before MPTP intoxication and repeated daily until sacrifice after MPTP intoxication. C57Bl/6 mice were injected intraperitoneally four times at 2 h intervals with either 20 mg/kg MPTP-HCl or a corresponding volume of saline. Two or seven days after the end of the MPTP intoxication, the animals were killed and their brains were processed for further analysis.
Treatment with PNU-282987 resulted in an attenuation of neuroinflammation in the MPTP-lesioned SN. Furthermore, PNU-282987 attenuated MPTP-induced dopaminergic cell loss in the SN and reduced striatal dopamine depletion. Unexpectedly, mecamylamine lowered neuroinflammation as well, though it did not show a neuroprotective potential at the nigral level.
Our results demonstrate the therapeutic potential of the selective α7 nicotinic acetylcholine agonist PNU-282987 in attenuating neuroinflammation and toxin-induced loss of dopaminergic neurons in the acute MPTP mouse model of PD.
Medical treatment of levodopa-induced dyskinesia (LID) in Parkinson's disease (PD) is an unmet need. ADS-5102 (amantadine) extended-release capsules is being developed for the treatment of LID in ...patients with PD.
Evaluate the long-term safety and tolerability of 274 mg ADS-5102 for LID in PD.
In an ongoing, open-label safety study (NCT02202551), PD patients with LID received 274 mg of ADS-5102 once daily at bedtime. Patients were recruited from previous ADS-5102 trials. In addition, patients were enrolled who were ineligible for previous ADS-5102 trials due to previous implantation of deep-brain stimulation (DBS) devices. The primary outcome measure was safety assessed through adverse events (AEs). Efficacy was assessed using the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS), Part IV and its subparts.
For this interim analysis, 223 patients received ADS-5102 for a mean duration of 348 (SD 182) days. The most common AEs included falls (25.1%), visual hallucinations (19.3%), peripheral edema (13.0%), and constipation (12.6%). Overall, 32 patients (14.3%) discontinued due to an AE. In patients receiving placebo in previous studies, the mean MDS-UPDRS, Part IV scores decreased by 3.4 points from baseline (n = 78) to week 8 and remained stable through week 64 (n = 21). In patients receiving ADS-5102 in previous studies, the mean baseline (n = 61) MDS-UPDRS, Part IV score was low due to the response to ADS-5102 in previous studies and remained stable through week 64 (total of 88 weeks; n = 21). The effect was primarily due to reduction in item 4.2 (functional impact of dyskinesia) and item 4.4 (functional impact of motor fluctuations).
ADS-5102 was generally well tolerated in all groups, including DBS patients, and the safety profile was consistent with previous controlled studies. Long-term durability and tolerability were shown from the double-blind studies through participation in the open-label study up to 88 weeks.
Inhibitory gamma-aminobutyric acidergic (GABAergic) neurons were identified in the dentate gyrus of seizure-sensitive (SS) and seizure-resistant (SR) gerbils by immunocytochemical localization of ...glutamic acid decarboxylase (GAD), the synthesizing enzyme for GABA. Increases in both the number of GAD+ somata and terminals were found in the dentate gyrus of the SS brains compared to the SR. The magnitude of the increase was positively correlated with the recorded seizure intensity. The increased number of GABAergic neurons in the dentate gyrus of SS gerbils could result in disinhibition of the granule cells, thereby allowing propagation of epileptiform activity through the hippocampus.
In the neocortex of an aged (26-year-old) rhesus monkey, a small percentage of abnormal neurites within some senile plaques (defined by the presence of amyloid) were immunoreactive for glutamic acid ...decarboxylase. This suggests that gamma-aminobutyric acid-synthesizing neurons may contribute to plaque formation in the aged brain.
Pharmacotherapy is the basis of treatment of Parkinson’s disease and there are effective medications, especially in the early stages. However, a number of possible side effects related to ...antiparkinsonian therapy need to be considered. This chapter describes nonmotor symptoms attributable to antiparkinsonian medication. These include rare but serious side effects such as serotonin syndrome and malignant neuroleptic syndrome. Data on chronic side effects such as ergotrelated fibrosis and cardiac valvulopathy are also reviewed in detail. Furthermore, medicationinduced fluctuation of mood, cognition and perception is exemplified. Lastly, the chapter describes how the disease process and dopamimetic medication contribute to excessive daytime sleepiness and notes advice for patients affected by this condition. A number of tables are included detailing the pharmacological properties and effects of selected dopamimetic drugs.
Hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency results in Lesch-Nyhan disease (LND), where affected individuals exhibit a characteristic neurobehavioral disorder that has been ...linked with dysfunction of dopaminergic pathways of the basal ganglia. Since the functions of HPRT, a housekeeping enzyme responsible for recycling purines, have no direct relationships with the dopaminergic pathways, the mechanisms whereby HPRT deficiency affect them remain unknown. The current studies demonstrate that HPRT deficiency influences early developmental processes controlling the dopaminergic phenotype, using several different cell models for HPRT deficiency. Microarray methods and quantitative PCR were applied to 10 different HPRT-deficient (HPRT−) sublines derived from the MN9D cell line. Despite the variation inherent in such mutant sublines, several consistent abnormalities were evident. Most notable were increases in the mRNAs for engrailed 1 and 2, transcription factors known to play a key role in the specification and survival of dopamine neurons. The increases in mRNAs were accompanied by increases in engrailed proteins, and restoration of HPRT reverted engrailed expression towards normal levels, demonstrating a functional relationship between HPRT and engrailed. The functional relevance of the abnormal developmental molecular signature of the HPRT− MN9D cells was evident in impoverished neurite outgrowth when the cells were forced to differentiate chemically. To verify that these abnormalities were not idiosyncratic to the MN9D line, HPRT− sublines from the SK-N-BE(2) M17 human neuroblastoma line were evaluated and an increased expression of engrailed mRNAs was also seen. Over-expression of engrailed occurred even in primary fibroblasts from patients with LND in a manner that suggested a correlation with disease severity. These results provide novel evidence that HPRT deficiency may affect dopaminergic neurons by influencing early developmental mechanisms.
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