The Japanese Journal of Pharmacology
Online ISSN : 1347-3506
Print ISSN : 0021-5198
ISSN-L : 0021-5198
Regular Papers
ATP-Sensitive Potassium Channels Regulate In Vivo Dopamine Release in Rat Striatum
Dawn Xiao-Dong ZhuJames P. SullivanJorge D.
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1999 Volume 79 Issue 1 Pages 59-64

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Abstract

ATP-sensitive K+ channels (KATP) are distributed in a variety of tissues including smooth muscle, cardiac and skeletal muscle, pancreatic β-cells and neurons. Since KATP channels are present in the nigrostriatal dopamine (DA) pathway, the effect of potassium-channel modulators on the release of DA in the striatum of conscious, freely-moving rats was investigated. The extracellular concentration of DA was significantly decreased by the KATP-channel opener (-)-cromakalim but not by diazoxide. (-)-Cromakalim was effective at 100 and 1000 μM concentrations, and the maximum decrease was 54% below baseline. d-Amphetamine significantly increased extracellular DA levels at the doses of 0.75 and 1.5 mg/kg, s.c. with a 770% maximum increase. (-)-Cromakalim had no effect on d-amphetamine-induced DA release, while glyburide, a KATP blocker, significantly potentiated the effects of a low dose of d-amphetamine. These data indicate that K+ channels present in the nigrostriatal dopaminergic terminals modulate basal release as well as evoked release of DA.

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© The Japanese Pharmacological Society 1999
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