TY - JOUR T1 - Converging Protein Kinase Pathways Mediate Adenylyl Cyclase Superactivation upon Chronic δ-Opioid Agonist Treatment JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 109 LP - 115 DO - 10.1124/jpet.103.049643 VL - 306 IS - 1 AU - Eva V. Varga AU - Marc K. Rubenzik AU - Dagmar Stropova AU - Masano Sugiyama AU - Vanessa Grife AU - Victor J. Hruby AU - Kenner C. Rice AU - William R. Roeske AU - Henry I. Yamamura Y1 - 2003/07/01 UR - http://jpet.aspetjournals.org/content/306/1/109.abstract N2 - Adenylyl cyclase (AC) superactivation is thought to play an important role in opioid tolerance, dependence, and withdrawal. In the present study, we investigated the involvement of protein kinases in chronic δ-opioid agonist-mediated AC superactivation in Chinese hamster ovary (CHO) cells stably expressing the human δ-opioid receptor (hDOR/CHO). Maximal forskolin-stimulated cAMP formation in hDOR/CHO cells increased by 472 ± 91, 399 ± 2, and 433 ± 73% after chronic treatment with the δ-opioid agonists (+)-4-[(αR)-α-((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxy-benzyl]-N,N-diethyl benzamide (SNC 80), [d-Pen2,d-Pen5]-enkephalin, and deltorphin II, respectively. Concurrently, chronic SNC 80 (1 μM, 4-h) treatment augmented 32P incorporation into a 200-kDa protein immunoreactive with the ACV/VI antibody by 300 ± 60% in hDOR/CHO cell lysates. The calmodulin antagonist calmidazolium significantly attenuated chronic deltorphin II-mediated AC superactivation. Tyrosine kinase (genistein) and protein kinase C (chelerythrine) inhibitors individually had minimal effect on chronic δ-opioid agonist-mediated AC superactivation. Conversely, simultaneous treatment with both genistein and chelerythrine significantly attenuated AC superactivation. Because we showed previously that the Raf-1 inhibitor 3-(3,5-dibromo-4-hydroxybenzylidene-5-iodo-1,3-dihydro-indol-2-one (GW5074) attenuates AC superactivation, we hypothesize that parallel calmidazolium-, chelerythrine-, and genistein-sensitive pathways converge at Raf-1 to mediate AC superactivation by phosphorylating AC VI in hDOR/CHO cells. The American Society for Pharmacology and Experimental Therapeutics ER -