Korean J Physiol Pharmacol.  2004 Aug;8(4):201-206.

Detection of Mitochondrial ATP-Sensitive Potassium Channels in Rat Cardiomyocytes

• Cuong DV
• Kim N
• Kim E
• Lee Y
• Kim H
• Kang S
• Hur DY
• Joo H
• Park YS
• Hong YG
• Lee S
• Chung J
• Seog D
• Han J

Abstract

Mitochondrial ATP-sensitive potassium (mitoKATP) channels play a role in early and late ischemic preconditioning. Nevertheless, the subunit composition of mitoKATP channels remains unclear. In this study, we investigated the subunit composition of mitoKATP channels in mitochondria isolated from rat cardiac myocytes. Mitochondria were visualized using the red fluorescence probe, Mitrotracker Red, while mitoKATP channels were visualized using the green fluorescence probe, glibenclamide-BODIPY. The immunofluorescence confocal microscopy revealed the presence of Kir6.1, Kir6.2 and SUR2 present in the cardiac mitochondria. Western blot analysis was carried to further investigate the nature of mitoKATP channels. For SUR proteins, a 140-kDa immunoreactive band that corresponded to SUR2, but no SUR1 was detected. For Kir6.2, three bands (~4, ~6, and ~0 kDa) were detected, and a specific ~6-kDa immunoreactive band corresponding to Kir6.1 was also observed. These observations suggest that the subunits of mitoKATP channels in rat myocytes include Kir6.1, Kir6.2, and a SUR2-related sulfonylurea-binding protein.

Keyword

Mitochondrial ATP-sensitive K+ channel; Ischemic preconditioning

MeSH Terms

Animals
Blotting, Western
Fluorescence
Fluorescent Antibody Technique
Ischemic Preconditioning
KATP Channels*
Microscopy, Confocal
Mitochondria
Muscle Cells
Myocytes, Cardiac*
Potassium
Rats*
KATP Channels
Potassium