RT Journal Article SR Electronic T1 β-Arrestin-dependent µ-opioid receptor-activated ERKs translocate to nucleus in contrast to G protein-dependent ERKs activation JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics DO 10.1124/mol.107.039842 A1 Hui Zheng A1 Horace H. Loh A1 Ping-Yee Law YR 2007 UL http://molpharm.aspetjournals.org/content/early/2007/10/18/mol.107.039842.abstract AB