This Article  • Full text  • PDF  • Send to a friend  • Save in My Folder  • Save to citation manager  • Permissions  Citing Articles  • Citation map  • Citing articles on HighWire  • Citing articles on ISI (6)  • Contact me when this article is cited  Related Content  • Similar articles in JAMA

	Since this article does not have an abstract, we have provided the first 150 words of the full text and any section headings.

To the Editor: Dr Marek and colleagues¹ reported that patients with Parkinson disease (PD) who were treated with pramipexole for 22 to 46 months had evidence of less dopamine neuron degeneration (as assessed by single-photon computed tomography [SPECT]) than did patients who were treated with levodopa for a similar period.

It is unclear whether these results simply reflect the pharmacological effects of pramipexole on dopamine transporter (DAT) expression, or the ability of DAT to sequester the radiologic marker 2-carboxymethoxy-3(4-iodophenyl)tropane (-CIT). If pramipexole simply increased DAT expression in surviving nerve terminals, imaging could falsely indicate more surviving neurons. Pramipexole alteration of DAT function might have a similar influence. Drugs that bind to dopaminergic receptors have significant effects on DAT phosphorylation, functions, expression, and turnover.² Dopamine agonists and levodopa can influence DAT synthesis and degradation, with D1- and D2-linked second messenger systems often affecting DAT expression in opposite ways.² . . . [Full Text of this Article]

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES

Selegiline slows the progression of the symptoms of Parkinson disease
Palhagen et al.
Neurology 2006;66:1200-1206.
ABSTRACT | FULL TEXT  

Neuroprotective agents for clinical trials in Parkinson's disease: A systematic assessment
Ravina et al.
Neurology 2003;60:1234-1240.
ABSTRACT | FULL TEXT  

Slowing Parkinson's disease progression: Recent dopamine agonist trials
Ahlskog
Neurology 2003;60:381-389.
ABSTRACT | FULL TEXT  

Initial agonist treatment of Parkinson disease: A critique
Albin and Frey
Neurology 2003;60:390-394.
ABSTRACT | FULL TEXT