Abstract | BACKGROUND: METHODS: Male Wistar rats were anesthetized with ether. Single, quiescent ventricular myocytes were dispersed enzymatically. Membrane currents were recorded using patch-clamp techniques. In the cell-attached configuration, KATP channel currents were assessed before and during activation of these channels by 2,4-dinitrophenol and after administration of 25, 50, and 100 mg/l thiamylal. The open probability was determined from current-amplitude histograms. In the inside-out configuration, the current-voltage relation was obtained before and after the application of thiamylal (50 mg/1). RESULTS: In the cell-attached configuration, 2,4-dinitrophenol caused frequent channel opening. 2,4-Dinitrophenol-induced channel activities were reduced significantly by glibenclamide, suggesting that the channels studied were KATP channels. Open probability of KATP channels was reduced by thiamylal in a concentration-dependent manner. KATP channels could be activated in the inside-out configuration because of the absence of ATP. Thiamylal inhibited KATP channel activity without changing the single-channel conductance. CONCLUSIONS: The results obtained in this study indicate that thiamylal inhibits KATP channel activities in cell-attached and inside-out patches, suggesting a direct action of this drug on these channels.
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Authors | Y Tsutsumi, S Oshita, H Kitahata, Y Kuroda, T Kawano, Y Nakaya |
Journal | Anesthesiology
(Anesthesiology)
Vol. 92
Issue 4
Pg. 1154-9
(Apr 2000)
ISSN: 0003-3022 [Print] United States |
PMID | 10754636
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- ATP-Binding Cassette Transporters
- Anesthetics, Intravenous
- KATP Channels
- Potassium Channels
- Potassium Channels, Inwardly Rectifying
- Uncoupling Agents
- uK-ATP-1 potassium channel
- Thiamylal
- 2,4-Dinitrophenol
- Glyburide
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Topics |
- 2,4-Dinitrophenol
(pharmacology)
- ATP-Binding Cassette Transporters
- Anesthetics, Intravenous
(pharmacology)
- Animals
- Cell Separation
- Electrophysiology
- Glyburide
(pharmacology)
- Heart
(drug effects)
- Heart Ventricles
(drug effects)
- In Vitro Techniques
- KATP Channels
- Male
- Membrane Potentials
(drug effects)
- Myocardial Ischemia
(physiopathology)
- Myocardium
(cytology)
- Patch-Clamp Techniques
- Potassium Channels
(adverse effects)
- Potassium Channels, Inwardly Rectifying
- Rats
- Rats, Wistar
- Thiamylal
(pharmacology)
- Uncoupling Agents
(pharmacology)
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