RT Journal Article SR Electronic T1 Regulation of Opioid Receptor Function by Chronic Agonist Exposure: Constitutive Activity and Desensitization JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 20 OP 25 DO 10.1124/mol.60.1.20 VO 60 IS 1 A1 Charles Chavkin A1 Jay P. McLaughlin A1 Jeremy P. Celver YR 2001 UL http://molpharm.aspetjournals.org/content/60/1/20.abstract AB