Xenopus oocytes expressed κ-opioid specific binding sites after injection of cRNA prepared from a clone of the rat κ-opioid receptor. Coinjection of κ receptor cRNA with cRNA coding for a G protein-linked, inwardly rectifying, K+ channel (GIRK1, or KGA) resulted in oocytes that responded to the κ agonist U-69593 by activating a large (1.0-1.5-μA) K+ current. U- 69593 exhibited an EC50 of 260 ± 50 nM and was blocked by the opioid antagonists norbinaltorphimine and naloxone. The κ 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 κ-opioid receptors.
|Original language||English (US)|
|Number of pages||7|
|State||Published - Mar 1 1995|
ASJC Scopus subject areas
- Molecular Medicine