Effects of Cl- channel blockers on the cardiac ATP-sensitive K+ channel
The Korean Journal of Physiology and Pharmacology
;
: 305-313, 1999.
Article
in English
| WPRIM
| ID: wpr-728244
ABSTRACT
To explore whether Cl- channel blockers interact with the ATP-sensitive K+ (KATP) channel, I have examined the effect of two common Cl- channel blockers on the KATP channel activity in isolated rat ventricular myocytes using patch clamp techniques. In inside-out patches, 4,4'-diisothio-cyanatostilbene-2,2'-disulfonic acid (DIDS) and niflumic acid applied to bath solution inhibited the KATP channel activity in a concentration-dependent manner with IC50 of 0.24 and 927 muM, respectively. The inhibitory action of DIDS was irreversible whereas that of niflumic acid was reversible. Furthermore, DIDS-induced block was not recovered despite exposure to ATP (1 mM). In cell-attached and inside-out patches, DIDS blocked the pinacidil- or 2,4-dinitrophenol (DNP)-induced KATP channel openings. In contrast, niflumic acid did not block the pinacidil-induced KATP channel openings in inside-out patches, but inhibited it in cell-attached patches. DIDS and niflumic acid produced additional block in the presence of ATP and did not affect current-voltage relationship and channel kinetics. All these results indicate that DIDS among Cl- channel blockers specifically blocks the cardiac KATP channel.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Baths
/
Kinetics
/
Adenosine Triphosphate
/
Niflumic Acid
/
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
/
Patch-Clamp Techniques
/
2,4-Dinitrophenol
/
Inhibitory Concentration 50
/
Muscle Cells
Type of study:
Diagnostic study
Limits:
Animals
Language:
English
Journal:
The Korean Journal of Physiology and Pharmacology
Year:
1999
Type:
Article
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