Journal article
β-Adrenergics enhance brain extraction of levodopa
Movement disorders, Vol.17(1), pp.54-59
01/2002
DOI: 10.1002/mds.10002
PMID: 28650123
Abstract
We sought to determine whether β-adrenergic agonists enhance the brain extraction of L-dopa and L-leucine. Systemic administration of β-adrenergic agonists increase brain concentrations of L-dopa and other large neutral amino acids (LNAA) in rats and monkeys and may improve symptoms and reduce daily L-dopa requirement in patients with Parkinson's disease. Cerebral blood flow (CBF) using [
H]nicotine and the extraction fraction of
C-labeled L-dopa or L-leucine were measured simultaneously in various brain regions of conscious rats using the dual-isotope indicator fractionation technique after intraperitoneal administration of isoproterenol (a peripheral nonselective β-adrenergic agonist), or clenbuterol (a β
-adrenergic agonist that crosses the blood-brain barrier), or β-adrenergic agonist preceded by nadolol (a peripheral nonselective β-adrenergic antagonist), or saline vehicle. Both β-adrenergic agonists increased regional brain extraction fraction of L-dopa and L-leucine tracers by 35-45%, without altering regional CBF. These changes were accompanied by about a 30% decrease in plasma branched chain LNAA concentrations. Nadolol blocked all these effects. β-Adrenergic agonists increase the brain extraction of L-dopa and leucine, mainly by peripheral mechanisms that reduce the levels of other competing plasma LNAAs for transport. Thus, β-adrenergic agonists might be useful in the treatment of patients with Parkinson's disease by enhancing delivery of L-dopa to the brain. © 2001 Movement Disorder Society.
Details
- Title: Subtitle
- β-Adrenergics enhance brain extraction of levodopa
- Creators
- Ergun Y Uc - Central Arkansas Veterans Healthcare System, Little Rock, Arkansas, USAGerald A Dienel - Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USANancy F Cruz - Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USASami I Harik - Central Arkansas Veterans Healthcare System, Little Rock, Arkansas, USA
- Resource Type
- Journal article
- Publication Details
- Movement disorders, Vol.17(1), pp.54-59
- Publisher
- United States
- DOI
- 10.1002/mds.10002
- PMID
- 28650123
- ISSN
- 0885-3185
- eISSN
- 1531-8257
- Language
- English
- Date published
- 01/2002
- Academic Unit
- Neurology
- Record Identifier
- 9984018151902771
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