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Ethanol opens G-protein-activated inwardly rectifying K+ channels.
T Kobayashi1, K Ikeda, H Kojima
1Department of Molecular Neuropathology, Brain Research Institute, Niigata University, 1-757 Asahimachi, Niigata, Niigata 951-8585, Japan. kobato@bri.niigata-u.ac.jp
Nature Neuroscience
|November 26, 1999
Summary
Ethanol directly activates G-protein-activated inwardly rectifying potassium (GIRK) channels in the brain and heart. This discovery reveals GIRK channels as key targets for ethanol
Area of Science:
- Neuroscience
- Pharmacology
- Cardiology
Background:
- Ethanol exerts widespread effects on the central nervous system and peripheral organs.
- G-protein-activated inwardly rectifying potassium (GIRK) channels are crucial for regulating neuronal excitability and heart rate.
Purpose of the Study:
- To investigate the direct interaction between ethanol and GIRK channels.
- To determine the role of GIRK channels in mediating the physiological effects of ethanol.
Main Methods:
- Electrophysiological recordings to assess ethanol's effect on GIRK channel activity.
- Pharmacological characterization of ethanol's interaction with different GIRK channel subtypes (GIRK1/2 and GIRK1/4).
- Behavioral studies using weaver mutant mice with a GIRK2 channel mutation to assess ethanol-induced analgesia.
Main Results:
- Ethanol directly activated brain-type GIRK1/2 and cardiac-type GIRK1/4 channels at pharmacologically relevant concentrations.
- Ethanol's activation of GIRK channels occurred independently of G protein or second messenger pathways.
- Weaver mutant mice lacking functional GIRK2 channels exhibited a loss of ethanol-induced analgesia.
Conclusions:
- GIRK channels are direct molecular targets for ethanol.
- Ethanol's modulation of GIRK channels in the brain and heart contributes to its physiological effects, including analgesia and regulation of neuronal excitability and heart rate.