Pflügers Archiv - European Journal of Physiology

, Volume 413, Issue 3, pp 325–327 | Cite as

Activation of atrial muscarinic K+ channels by low concentrations ofβγ subunits of rat brain G protein

  • Yoshihisa Kurachi
  • Hiroyuki Ito
  • Tsuneaki Sugimoto
  • Toshiaki Katada
  • Michio Ui
Excitable Tissues Cand Central Nervous Physiology Short Communication


Effects of G protein βγ subunits from rat brain on cardiac K+ channel was examined in single atrial cells of guinea-pig, using patch clamp techniques. We found that 10 pM concentration of rat brain βγ subunits preparation could activate the atrial muscarine receptor-gated K+ channel (IK.ACh). Neither the detergent, CHAPS, used to suspend βγ nor the boiled βγ preparation activated IK.ACh. Furthermore, preincubation of βγ subunits preparation in Mg2+-free solution, which easily inactivated α-GTP-γS, did not affect βγ-activation of IK.ACh. We concluded, therefore, that βγ subunits themselves can activate IK.ACh.

Key Words

muscarine receptor-gated K+ channel GTP-binding protein subunits cardiac atrial cells 


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Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Yoshihisa Kurachi
    • 1
  • Hiroyuki Ito
    • 1
  • Tsuneaki Sugimoto
    • 1
  • Toshiaki Katada
    • 2
  • Michio Ui
    • 3
  1. 1.The 2nd Department of Internal Medicine, Faculty of MedicineUniversity of TokyoTokyoJapan
  2. 2.Department of Life Science, Faculty of ScienceTokyo Institute of TechnologyYokohamaJapan
  3. 3.Department of Physiological Chemistry, Faculty of Pharmaceutical SciencesUniversity of TokyoTokyoJapan

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