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Channels (Austin). 2008 Jul-Aug;2(4):269-77. Epub 2008 Jul 9.

D2 dopamine receptors interact directly with N-type calcium channels and regulate channel surface expression levels.

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1
Department of Physiology and Biophysics, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.

Abstract

N-type channels are located on dendrites and at pre-synaptic nerve terminals where they play a fundamental role in neurotransmitter release. They are potently regulated by the activation of a number of different types of pertussis toxin (PTX)-sensitive G alpha(i/o) coupled receptors, which results in voltage-dependent inhibition of channel activity via G betagamma subunits. Using heterologous expression in HEK 293T cells, we show via whole cell patch clamp recordings that D2 receptors mediate both G betagamma (i.e., voltage-dependent) and voltage-independent inhibition of channel activity. Furthermore, using co-immunoprecipitation and pull down assays involving the intracellular regions of each protein, we show that D2 receptors and N-type channels form physical signaling complexes. Finally, we use confocal microscopy to demonstrate that D2 receptors regulate N-type channel trafficking to affect the number of calcium channels available at the plasma membrane. Taken together, these data provide evidence for multiple voltage-dependent and voltage-independent mechanisms by which D2 receptor subtypes influence N-type channel activity.

PMID:
18719394
[Indexed for MEDLINE]
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