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D1-Receptor Impact on Neuroplasticity in Humans.
- Source :
- Journal of Neuroscience; 2/25/2009, Vol. 29 Issue 8, p2648-2653, 6p, 2 Diagrams, 1 Chart
- Publication Year :
- 2009
-
Abstract
- Dopamine improves learning and memory formation. The neurophysiological basis for these effects might be a focusing effect of dopamine on neuroplasticity: Accordingly, in humans L-dopa prolongs focal facilitatory plasticity, but turns nonfocal facilitatory plasticity into inhibition. Here we explore the impact of D<subscript>1</subscript> receptors on plasticity. Nonfocal plasticity was induced by transcranial direct current stimulation (tDCS), and focal plasticity by paired associative stimulation (PAS). Subjects received sulpiride, a D<subscript>2</subscript> antagonist, to increase the relative contribution of D<subscript>1</subscript> receptors to dopaminergic activity, combined sulpiride and L-dopa, to increase the relation of D<subscript>1</subscript>/D<subscript>2</subscript> activity further, or placebo medication. Under placebo, anodal tDCS and excitatoryPAS(ePAS) increased motor cortex excitability. Cathodal tDCS and inhibitory PAS (iPAS) reduced it. Sulpiride abolished iPAS-induced inhibition, but not ePAS-generated facilitation, underlining the importance of D<subscript>1</subscript>-receptor activity for focal facilitatory neuroplasticity. Combining sulpiride with L-dopa reestablished iPAS-induced inhibition, but did not affect ePAS-induced plasticity. tDCS-induced plasticity, which was abolished by sulpiride in a former study, also recovered. Thus enhancing D<subscript>1</subscript> activity further relative to D<subscript>2</subscript> activity is relevant for facilitatory and inhibitory plasticity. However, comparison with former results show that an appropriate balance of D<subscript>1</subscript> and D<subscript>2</subscript> activity seems necessary to (1) consolidate the respective excitability modifications and (2) to elicit a focusing effect. [ABSTRACT FROM AUTHOR]
- Subjects :
- NEURAL receptors
NEUROPLASTICITY
DOPAMINE
NEUROPHYSIOLOGY
PLACEBOS
Subjects
Details
- Language :
- English
- ISSN :
- 02706474
- Volume :
- 29
- Issue :
- 8
- Database :
- Complementary Index
- Journal :
- Journal of Neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 36901844
- Full Text :
- https://doi.org/10.1523/JNEUROSCI.5366-08.2009