ISSN:
1432-1424
Keywords:
Key words: Potassium channel — Adenosine — Adenosine triphosphate (ATP) — Skeletal muscle
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract. We investigated the action of adenosine and GTP on KATP channels, using inside-out patch clamp recordings from dissociated single fibers of rat flexor digitorum brevis (FDB) skeletal muscle. In excised patches, KATP channels could be activated by a combination of an extracellular adenosine agonist and intracellular Mg2+-ATP and GTP or GTP-γ-S. The activation required hydrolyzable ATP and could be partially reversed with Mg2+, suggesting that it may involve a G-protein dependent phosphorylation of KATP channels. We found that KATP channels of the rat FDB could not be activated by Mg2+-ATP alone or by Mg2+-ATP in the presence of extracellular adenosine. Patches whose channel activity had been `rundown' by Ca2+ could not be recovered by adenosine, GTP or Mg2+-ATP. KATP channels activated by adenosine receptor agonists had a similar ATP sensitivity to those under control conditions; but adenosine appears to be able to switch these KATP channels from an inactive to an active mode.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s002329900090
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