Inwardly rectifying K+ currents in gastric myocytes of guinea-pig

Jae Yeoul Jun, 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

Research output: Contribution to journalArticlepeer-review

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.

Original languageEnglish
Pages (from-to)47-55
Number of pages9
JournalKorean Journal of Physiology and Pharmacology
Volume6
Issue number1
Publication statusPublished - 2002

All Science Journal Classification (ASJC) codes

  • Physiology
  • Pharmacology

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