Activation of muscarinic K+ current by beta-adrenergic receptors in cultured atrial myocytes transfected with beta1 subunit of heterotrimeric G proteins.
Muscarinic K+ channels (IK(ACh)) in native atrial myocytes are activated by betagamma subunits of pertussis toxin (Ptx)-sensitive heterotrimeric G proteins coupled to different receptors. betagamma subunits of Ptx-insensitive Gs, coupled to beta-adrenergic receptors, do not activate native IK(ACh). In atrial myocytes from adult rats transfected with rat brain beta1 subunit IK(ACh) can be activated by stimulation of beta-adrenergic receptors using isoprenaline. This effect is insensitive to Ptx. These findings demonstrate for the first time promiscuous (Ptx-insensitive) coupling of Gsbetagamma to GIRK channels in their native environment.
Bender
K
K
Institut für Physiologie, Abteilung Zelluläre Physiologie, Ruhr-Universität Bochum, Germany.
Wellner-Kienitz
M C
MC
Meyer
T
T
Pott
L
L
D000818:Animals; D016275:Atrial Function / Q000502:physiology; D002478:Cells, Cultured; D005260:Female; D019204:GTP-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D006321:Heart / Q000502:physiology; D008297:Male; D008564:Membrane Potentials; D009206:Myocardium / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011943:Receptors, Adrenergic, beta / Q000378:metabolism / Q000502:physiology*
D015221:Potassium Channels; D011943:Receptors, Adrenergic, beta; D019204:GTP-Binding Proteins