Inwardly Rectifying K+ Currents in Gastric Myocytes of Guinea-pig.
- Author:
Jae Yeoul JUN
1
;
Cheol Ho YEUM
;
Pyung Jin YOON
;
In Youb JANG
;
Nam Soo CHO
;
Soo Hyeong CHO
;
In Deok KONG
;
Tae Wan KIM
;
Insuk SO
;
Ki Whan KIM
Author Information
1. Department of Physiology, College of Medicine, Chosun University, Korea. insuk@plaza.sun.ac.kr
- Publication Type:Original Article
- Keywords:
Inwardly rectifying K+ channels;
Ba2+-sensitive currents;
Gastric myocytes
- MeSH:
Baths;
Glyburide;
Membranes;
Muscle Cells*;
Muscle, Smooth;
Tea
- From:The Korean Journal of Physiology and Pharmacology
2002;6(1):47-56
- CountryRepublic of Korea
- Language:English
-
Abstract:
To identify the presence of inwardly rectifying K+ channels and its characteristics, membrane currents were measured using a whole-cell patch clamp from isolated gastric myocytes of guinea-pig. Change of external K+ concentration from 5 to 90 mM induced an inward current at a holding potential of 80 mV. The high K+-induced inward current was blocked by Ba2+ and Cs+, but not by glibenclamide. With 90 mM K+ in bath, the Ba2+- and Cs+-sensitive currents showed strong inward rectification. Ten mM TEA weakly blocked the inward current only at potentials more negative than 50 mV. With 90 mM K+ in bath, hyperpolarizing step pulses from 10 mV induced inward currents, which were inactivated at potentials more negative than 70 mV. Reduction of external K+ to 60 mM decreased the amplitudes of the currents and shifted the reversal potential to more negative potential. The inactivation of inward K+ current at negative clamp voltage was not affected by removing external Na . These results suggest that the inwardly rectifying K+ channels may exist in gastric smooth muscle.
