RT Journal Article
SR Electronic
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
FD American Society for Pharmacology and Experimental Therapeutics
SP 109
OP 115
DO 10.1124/jpet.103.049643
VO 306
IS 1
A1 Eva V. Varga
A1 Marc K. Rubenzik
A1 Dagmar Stropova
A1 Masano Sugiyama
A1 Vanessa Grife
A1 Victor J. Hruby
A1 Kenner C. Rice
A1 William R. Roeske
A1 Henry I. Yamamura
YR 2003
UL http://jpet.aspetjournals.org/content/306/1/109.abstract
AB 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