Kawano T, Tanaka K, Yinhua, Eguchi S, Kawano H, Takahashi A, Nakaya Y, Oshita S. Effects of ketamine on nicorandil induced ATP-sensitive potassium channel activity in cell line derived from rat aortic smooth muscle.
THE JOURNAL OF MEDICAL INVESTIGATION 2011;
57:237-44. [PMID:
20847523 DOI:
10.2152/jmi.57.237]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
PURPOSE
Nicorandil opens adenosine triphosphate-sensitive potassium (K(ATP)) channels in the cardiovascular system and is being increasingly used for the treatment of angina pectoris. In the present study, we tested whether intravenous anesthetic agent ketamine affected nicorandil-induced native vascular K(ATP) channel activation.
METHODS
We used excised inside-out patch clamp configurations to investigate the direct effects of ketamine racemate and S-(+)-ketamine on the activities of K(ATP) channels in cultured rat aortic smooth muscle cells. Furthermore, we also investigated whether intracellular MgADP could modulate ketamine inhibition.
RESULTS
Nicorandil significantly activated K(ATP) channel activity, whereas this channel activity was completely blocked by glibenclamide, a specific K(ATP) channel blocker. Ketamine racemate inhibited the nicorandil induced K(ATP) channel activity (IC(50)=34±1 µM, n=14), but S-(+)-ketamine was less potent than ketamine racemate in blocking nicorandil induced K(ATP) channel activities (IC(50)=226±7 µM, n=10). Application of MgADP to the intracellular side of the channel was able to decrease the inhibitory potency of ketamine racemate on nicorandil induced K(ATP) channel activities.
CONCLUSIONS
Our results indicate that ketamine inhibits nicorandil induced K(ATP) channel activities in a dose dependent and stereoselective manner. Furthermore, increase of intracellular MgADP attenuates the inhibitory potency of ketamine racemate. J. Med. Invest. 57: 237-244, August, 2010.
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