Expression of an atrial G-protein-activated potassium channel in Xenopus oocytes

Citations of this article
Mendeley users who have this article in their library.


Injection of rat atrial RNA into Xenopus oocytes resulted in the expression of a guanine nucleotide binding (G) protein-activated K+ channel. Current through the channel could be activated by acetylcholine or, if RNA encoding a neuronal 5HT1A receptor was coinjected with atrial RNA, by serotonin (5HT). A 5HT-evoked current (1(5HT)) was observed in oocytes injected with ventricle RNA fractions (of 2.5-5.5 kb) and 5HT1A receptor RNA. 1(5HT) displayed strong inward rectification with very little conductance above the K+ equilibrium potential, was highly selective for K+ over Na+, and was blocked by 5-300 μM Ba2+. 1(5HT) was suppressed by intracellular injection of the nonhydrolyzable analog of GDP, guanosine 5'-[β- thio]diphosphate, but not by treatment with pertussis toxin (PTX), suggesting coupling of the receptor to the G-protein-activated K+ channel via a PTX- insensitive G protein, possibly endogenously present in the oocyte. Coexpression of the α subunit of a PTX-sensitive G protein, G(i2), rendered 1(5HT) sensitive to PTX inhibition. Native oocytes displayed a constitutively active inwardly rectifying K+ current with a lower sensitivity to Ba2+ block; expression of a similar current was also directed by atrial or ventricle RNA of 1.5-3 kb. Xenopus oocytes may be employed for cloning of the G-protein-activated K+ channel cDNA and for studying the coupling between this channel and G proteins.




Dascal, N., Lim, N. F., Schreibmayer, W., Wang, W., Davidson, N., & Lester, H. A. (1993). Expression of an atrial G-protein-activated potassium channel in Xenopus oocytes. Proceedings of the National Academy of Sciences of the United States of America, 90(14), 6596–6600.

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free