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

Pflugers Arch. 1989 Jan;413(3):325-7. doi: 10.1007/BF00583550.


Effects of G protein beta gamma 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 beta gamma subunits preparation could activate the atrial muscarine receptor-gated K+ channel (IK.ACh). Neither the detergent, CHAPS, used to suspend beta gamma nor the boiled beta gamma preparation activated IK.ACh. Furthermore, preincubation of beta gamma subunits preparation in Mg2+-free solution, which easily inactivated alpha-GTP-gamma S, did not affect beta gamma-activation of IK.ACh. We concluded, therefore, that beta gamma subunits themselves can activate IK.ACh.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / metabolism
  • Animals
  • GTP-Binding Proteins / pharmacology*
  • Guinea Pigs
  • Heart Atria / cytology
  • Myocardium / cytology
  • Myocardium / metabolism*
  • Potassium Channels / drug effects
  • Potassium Channels / metabolism*
  • Rats
  • Receptors, Muscarinic / drug effects
  • Receptors, Muscarinic / metabolism*


  • Potassium Channels
  • Receptors, Muscarinic
  • GTP-Binding Proteins
  • Acetylcholine