The present study investigated the effects of levodopa, a precursor of dopamine (DA) therapeutically used for the treatment of Parkinson's disease, on DA transport in the two different systems, COS-7 cells heterologously expressing rat monoamine transporter cDNA and in monoaminergic cell lines PC12 and SK-N-SH. Levodopa enhanced uptake of [3H]DA and [3H]norepinephrine (NE) but not [3H]serotonin...

Fifty four patients with idiopathic Parkinson's disease receiving levodopa therapy were studied. Thirty three of these patients displayed peak-dose dyskinesia. Neither the duration of Parkinson's disease nor the duration of levodopa therapy discriminated between patients with and patients without peak-dose dyskinesia. Consequently, these criteria could not determine whether the first appearance...

One hundred and twenty nine de novo patients with idiopathic Parkinson's disease are being followed over a 5 year period in a double-blind multicentre study comparing low-dose bromocriptine (less than 30 mg/day) with low-dose levodopa-carbidopa (less than 600/150 mg/day). Sixty six patients have been randomised to bromocriptine and 63 patients to levodopa-carbidopa. Improvement has been greater...

Intravenous levodopa has been used in a multitude of research studies due to its more predictable pharmacokinetics compared to the oral form, which is used frequently as a treatment for Parkinson's disease (PD). Levodopa is the precursor for dopamine, and intravenous dopamine would strongly affect vascular tone, but peripheral decarboxylase inhibitors are intended to block such effects. Pulse a...

The development of in vitro investigation models could be important using sensitive and fast methods during formulation. Intranasal applied drugs (meloxicam, lamotrigine, levodopa) avoid the gastrointestinal tract can achieve higher bioavailability, therefore a penetration extent is key property. In this study, adaptability modified horizontal diffusion cell was tested by these model active pha...

Parkinson’s disease (PD) is the second most common neurodegenerative disorder. Pharmacotherapy with levodopa in combination with carbidopa provides symptomatic relief in patients suffering from PD. However, several studies have been conducted in an attempt to improve the therapeutic efficiency of levodopa by using drugs that preferentially inhibit extracerebral decarboxylase. Yet, none of them ...

BACKGROUND Levodopa-induced dyskinesias are a common side effect of dopaminergic therapy in PD, but their neural correlates remain poorly understood. OBJECTIVES This study examines whether dyskinesias are associated with abnormal dopaminergic modulation of resting-state cortico-striatal connectivity. METHODS Twelve PD patients with peak-of-dose dyskinesias and 12 patients without dyskinesia...

A case-control study was designed to investigate a possible genetic susceptibility of the MTHFR C677T polymorphism and assess whether the genetic polymorphism could be a predictor of levodopa-induced adverse effects in patients with Parkinson's disease (PD) of Chinese descent living in Taiwan. There were 94 sporadic PD patients with levodopa therapy at least for five years and 146 control subje...

Background. It is often difficult to differentiate Parkinson's disease (PD) from multiple system atrophy (MSA), especially in their early stages. Objectives. To examine the clinical utility of histopathological analysis of biopsied skin from the chest wall and/or leg in differentiating between the two diseases. Methods. Skin biopsies from the lower leg and/or anterior chest wall were obtained f...

The effectiveness of oral levodopa in complex Parkinson's disease (PD) is limited by its short half-life, and the resulting pulsatile dopaminergic stimulation leads to complex motor fluctuations and dyskinesia. Several treatments provide more continuous/less pulsatile dopaminergic stimulation by modifying the pharmacokinetics of levodopa or dopamine; however, patients with advanced disease can ...