Ca2+-activated K+ Current in Freshly Isolated c-Kit Positive Cells in Guinea-pig Stomach.
10.3346/jkms.2009.24.3.384
- Author:
Young Chul KIM
1
;
Hikaru SUZUKI
;
Wen Xie XU
;
Woong CHOI
;
Seok Hyung KIM
;
Sang Jin LEE
Author Information
1. Department of Physiology, Chungbuk National University, College of Medicine, Cheongju, Korea. physiokyc@chungbuk.ac.kr
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
Interstitial Cells of Cajal;
Stomach;
Potassium Channels, Calcium-Activated;
Spontaneous Inward Current;
Guinea Pig
- MeSH:
Animals;
Calcium/*metabolism;
Guinea Pigs;
Membrane Potentials/drug effects;
Patch-Clamp Techniques;
Peptides/pharmacology;
Potassium Channels/drug effects/*physiology;
Proto-Oncogene Proteins c-kit/*metabolism;
Pyloric Antrum/cytology/*physiology;
Tetraethylammonium/pharmacology
- From:Journal of Korean Medical Science
2009;24(3):384-391
- CountryRepublic of Korea
- Language:English
-
Abstract:
This study was designed to isolate Ca2+-activated K+ current (IKCa) and elucidate its physiological significance in freshly isolated interstitial cells of Cajal (ICCs) of guinea-pig stomach. Single ICC was freshly isolated by enzymatically dissociating from myenteric border of gastric antrum free of circular muscles, and conventional whole-cell voltage clamp technique including immunohistochemical techniques were employed to characterize the cells: In myenteric border of gastric antrum, ICC-MY (ICCs from myenteric border) were detected by immunohistochemical reactivity, and single ICC-MY which has many branches was immunohistochemically c-Kit positive. Under K+-rich and 0.1 mM ethylene glycol-bis (2-aminoethyl ether)-N,N,N',N'-tetraacetic acid pipette solution, ICC produced spontaneous inward current (-256+/-92.2 pA). When step-depolarizing pulse from -80 to +80 mV was applied at holding potential (Vh) of -80 mV, voltage-dependent outward currents were recorded with superimposed spontaneous transient outward currents (STOCs). Both STOCs and outward currents were reversibly affected by tetraethylammonium chloride (TEA) and iberiotoxin (IbTX); 2 mM TEA and 200 nM IbTX completely abolished STOCs and significantly inhibited outward K+ current over the whole potential range tested for current/voltage (I/V) relationship. In addition, TEA delayed repolarization phase of spontaneous inward current. The present results indicate the presence of IKCa in a single ICC, and it might be involved in regulation of repolarizing phase of spontaneous inward current in guinea-pig stomach.
