TY - JOUR T1 - Kappa-opioid receptors couple to inwardly rectifying potassium channels when coexpressed by Xenopus oocytes. JF - Molecular Pharmacology JO - Mol Pharmacol SP - 551 LP - 557 VL - 47 IS - 3 AU - D J Henry AU - D K Grandy AU - H A Lester AU - N Davidson AU - C Chavkin Y1 - 1995/03/01 UR - http://molpharm.aspetjournals.org/content/47/3/551.abstract N2 - Xenopus oocytes expressed kappa-opioid specific binding sites after injection of cRNA prepared from a clone of the rat kappa-opioid receptor. Coinjection of kappa receptor cRNA with cRNA coding for a G protein-linked, inwardly rectifying, K+ channel (GIRK1, or KGA) resulted in oocytes that responded to the kappa agonist U-69593 by activating a large (1.0-1.5-microA) K+ current. U-69593 exhibited an EC50 of 260 +/- 50 nM and was blocked by the opioid antagonists norbinaltorphimine and naloxone. The kappa agonist bremazocine was 200-fold more potent than U-69593 in eliciting K+ current but exhibited a partial agonist profile in this expression system. The present results indicate that stimulation of inwardly rectifying K+ channels may be a potential effector mechanism for kappa-opioid receptors. ER -