Activation of the Cardiac ATP-Sensitive K+Channel by KR-30816,Newly Synthesized Potassium Channel Opener.
10.4070/kcj.1994.24.6.889
- Author:
Kyoung Suk RHEE
;
Jae Ki KO
;
Yong Geun KWAK
;
Soo Wan CHAE
- Publication Type:Original Article
- Keywords:
KR-30816;
Potassium channel opener;
ATP-sensitive K+channel;
Action potential;
Patch clamp technique;
Heart
- MeSH:
Action Potentials;
Adenosine Triphosphate;
Animals;
Guinea Pigs;
Heart;
Microelectrodes;
Muscle Cells;
Papillary Muscles;
Potassium Channels*;
Potassium*;
Rats;
Uridine Diphosphate
- From:Korean Circulation Journal
1994;24(6):889-898
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: The effects of a newly synthesized potassium channel opener, KR-30816((-)(nitro-2-hydroxymethyl-2-methy-2H-1-benzopyran-4-y1)pyridine oxide) on the action potential of papillary muscles of guinea pigs and the ATP-sensitive potassium channel current(IKATP) of single ventricular muscle cells of rats were examined to make clear its action mechanism of the KATPchannel. METHODS: We used the conventional microelectrode and the excised inside-out patch configuration. RESULTS: KR-30816 caused a shortening of the action potential duration in dose-dependent manner, which was inhibited by glibenclamide(3microM). Before run-down of the K+channel, KR-30816 activated the cardiac ATP-sensitive K+ channel only in the presence of ATP and shifted the dose-response relation curve between [ATP]i and the channel activity to the right in parallel. After run-down of the KATP channel, KR-30816 did not after the channel opening either in the absence or in the presence of UDP. CONCLUSION: These results suggest that KR-30816 antagonizes the inhibitory effect of ATP on the KATPchannel in a competitive manner, thereby enhancing the channel openings.
