Dopamine dysregulation in a mouse model of paroxysmal nonkinesigenic dyskinesia
Hsien-yang Lee, Junko Nakayama, Ying Xu, Xueliang Fan, Maha Karouani, Yiguo Shen, Emmanuel N. Pothos, Ellen J. Hess, Ying-Hui Fu, Robert H. Edwards, Louis J. Ptácek
Hsien-yang Lee, Junko Nakayama, Ying Xu, Xueliang Fan, Maha Karouani, Yiguo Shen, Emmanuel N. Pothos, Ellen J. Hess, Ying-Hui Fu, Robert H. Edwards, Louis J. Ptácek
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Research Article Neuroscience

Dopamine dysregulation in a mouse model of paroxysmal nonkinesigenic dyskinesia

Abstract

Paroxysmal nonkinesigenic dyskinesia (PNKD) is an autosomal dominant episodic movement disorder. Patients have episodes that last 1 to 4 hours and are precipitated by alcohol, coffee, and stress. Previous research has shown that mutations in an uncharacterized gene on chromosome 2q33–q35 (which is termed PNKD) are responsible for PNKD. Here, we report the generation of antibodies specific for the PNKD protein and show that it is widely expressed in the mouse brain, exclusively in neurons. One PNKD isoform is a membrane-associated protein. Transgenic mice carrying mutations in the mouse Pnkd locus equivalent to those found in patients with PNKD recapitulated the human PNKD phenotype. Staining for c-fos demonstrated that administration of alcohol or caffeine induced neuronal activity in the basal ganglia in these mice. They also showed nigrostriatal neurotransmission deficits that were manifested by reduced extracellular dopamine levels in the striatum and a proportional increase of dopamine release in response to caffeine and ethanol treatment. These findings support the hypothesis that the PNKD protein functions to modulate striatal neuro­transmitter release in response to stress and other precipitating factors.

Authors

Hsien-yang Lee, Junko Nakayama, Ying Xu, Xueliang Fan, Maha Karouani, Yiguo Shen, Emmanuel N. Pothos, Ellen J. Hess, Ying-Hui Fu, Robert H. Edwards, Louis J. Ptácek

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Figure 2

PNKD-L is a membrane-associated protein.

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PNKD-L is a membrane-associated protein. (A) Immunostaining studies of p...
(A) Immunostaining studies of permeabilized and nonpermeabilized HEK293 cells indicate that PNKD-L is a membrane-associated protein. HEK293 cells are transfected with PNKD-EGFP followed by immunohistochemical staining using N- and C-terminal PNKD antibodies and Cy3-conjugated goat anti-rabbit IgG secondary antibody. Both PNKD N- and C-terminal antibodies detect transfected PNKD-L–EGFP in permeabilized HEK cells, but fail to detect it in nonpermeabilized HEK cells. Scale bars: 10 microns. (B) Detergent phase partitioning of HEK293 membrane fraction transfected with PNKD-L–EGFP. The PNKD-L–EGFP (~75 kDa) can be detected in crude membrane fraction by both PNKD antibodies, but after TX-114 treatment, the PNKD-L–EGFP can be detected in the hydrophilic layer, but not in the hydrophobic layer.