Activation of inwardly rectifying K+ channels by GABA-B receptors expressed in Xenopus oocytes.
In Xenopus oocytes coinjected with poly(A)+ RNA derived from the rat cerebellum and cRNAs for the cloned G protein-gated inwardly rectifying K+ channel (GIRK), GIRK1 and GIRK2, the GABA-B agonist baclofen elicited inwardly rectifying K+ currents. The inward K+ currents elicited by baclofen were inhibited by the selective GABA-B antagonists 2-OH saclofen and CGP 35348, and by the GIRK inhibitor Ba2+. In contrast, baclofen caused no currents in oocytes injected with the cerebellar poly(A)+ RNA alone, the poly(A)+ RNA and cRNA for GIRK1 or GIRK2, or only cRNAs for GIRK1 and GIRK2. These findings indicate that GABA-B receptors in the rat cerebellum were functionally expressed in Xenopus oocytes and activated the cloned GIRKs composed of GIRK1 and GIRK2 as heteromultimers.
Uezono
Y
Y
Department of Pharmacology, University of Occupational and Environmental Health, School of Medicine, Kitakyushu, Japan.
Akihara
M
M
Kaibara
M
M
Kawano
C
C
Shibuya
I
I
Ueda
Y
Y
Yanagihara
N
N
Toyohira
Y
Y
Yamashita
H
H
Taniyama
K
K
Izumi
F
F
D000818:Animals; D001418:Baclofen / Q000031:analogs & derivatives / Q000494:pharmacology*; D002531:Cerebellum / Q000378:metabolism; D005260:Female; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D018756:GABA Antagonists / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009118:Muscimol / Q000494:pharmacology; D009865:Oocytes / Q000502:physiology; D009943:Organophosphorus Compounds / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000096:biosynthesis / Q000502:physiology*; D024661:Potassium Channels, Inwardly Rectifying; D051381:Rats; D018080:Receptors, GABA-B / Q000096:biosynthesis / Q000502:physiology*; D011994:Recombinant Proteins / Q000096:biosynthesis; D014982:Xenopus laevis
D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; D018756:GABA Antagonists; D009943:Organophosphorus Compounds; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D018080:Receptors, GABA-B; D011994:Recombinant Proteins; D009118:Muscimol; C066430:CGP 35348; D019204:GTP-Binding Proteins; D001418:Baclofen; C057491:2-hydroxysaclofen