Effect of pH on the ATP-sensitive K+ channel in aortic smooth muscle cells from rats.
- Author:
Se Hoon KIM
1
;
Il Su KIM
;
Hoe Suk KIM
;
Byeong Hwa JEON
;
Seok Jong CHANG
Author Information
1. Department of Physiology, College of Medicine, Chungnam National University, Daejeon 301-131, South Korea.
- Publication Type:Original Article
- Keywords:
pH;
K+-channel;
Vascular smooth muscle;
Pinacidil;
Glibenclamide
- MeSH:
Adenosine Triphosphate;
Animals;
Aorta, Thoracic;
Glyburide;
Hydrogen-Ion Concentration*;
Muscle, Smooth*;
Muscle, Smooth, Vascular;
Myocytes, Smooth Muscle*;
Patch-Clamp Techniques;
Pinacidil;
Rats*
- From:The Korean Journal of Physiology and Pharmacology
1997;1(5):555-563
- CountryRepublic of Korea
- Language:English
-
Abstract:
The effects of pH on K+ currents were investigated in single smooth muscle cells isolated from the thoracic aorta of Wistar-Kyoto rats. Whole-cell K+ currents were recorded in the conventional configuration of the voltage-clamp technique. Pinacidil (10muM) activated the whole-cell current and the pinacidil-activated current was completely inhibited by glibenclamide (10muM), an inhibitor of ATP-sensitive K+ channel (KATP channel). Pinacidil-activated current was reversed at near the K+ equilibrium potential. This current was time- and voltage-independent and reduced by elevating intracellular ATP. Pinacidil-activated current was reduced by lowering the external pH. However, alteration of internal pH has controversial effects on pinacidil-activated current. When the single cell was dialyzed with 0.1 mM ATP, alteration of internal pH had no effect on pinacidil-activated K+ current. In the contrast, when the single cell was dialyzed with 3 mM ATP, pinacidil-activated current was increased by lowering internal pH. Our results suggest that K+ channel activated by pinacidil may be KATP channel and internal H+ may reduce the inhibitory effect of ATP on KATP channel.
