Anatomical and physiological evidence for D-1 and D-2 dopamine receptor colocalization in neostriatal neurons

• Despite the importance of dopamine signaling, it remains unknown if the two major subclasses of dopamine receptors exist on the same or distinct populations of neurons. Here we used confocal microscopy to demonstrate that virtually all striatal neurons, both in vitro and in vivo, contained dopamine receptors of both classes. We also provide functional evidence for such colocalization: in essentially all neurons examined, fenoldopam, an agonist of the D-1 subclass of receptors, inhibited both the Na+/K+ pump and tetrodotoxin (TTX)-sensitive sodium channels, and quinpirole, an agonist of the Dr subclass of receptors, activated TTX-sensitive sodium channels. Thus D-1 and D-2 classes of ligands may functionally interact in virtually all dopamine-responsive neurons within the basal ganglia.

Nyckelord

Striatal neurons

gene-expression

basal ganglia

hela-cells

rat

na

k-atpase

isoforms

localization

darpp-32

sodium

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MEDICIN

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