title: Role of protein kinase C-epsilon in the development of kappa-opioid receptor tolerance to U50,488H in rat ventricular myocytes.
abstract: The role of protein kinase C-epsilon (PKC-epsilon) in the development of kappa-opioid receptor (kappa-OR) tolerance to the effects of trans-(+/-)-3,4-dichloro-N-methyl-N-(2-[1-pyrrolidinyl]cyclohexyl) (U50,488H), the selective agonist of kappa-OR, was determined in rat ventricular myocytes. Incubation of ventricular myocytes with 1 microM U50,488H for 24 h significantly attenuated the inhibitory effects of 30 microM U50,488H on the electrically-induced [Ca(2+)](i) transient and forskolin-stimulated cyclic AMP accumulation, indicating the development of tolerance to the kappa-OR agonist. Chronic treatment of ventricular myocytes with U50,488H also induced translocation of PKC-epsilon to the particulate fraction. On the other hand, administration of 30 microM U50,488H for 10 min induced translocation of PKC-alpha to the particulate fraction in naïve ventricular myocytes, but not in cells pretreated with 1 microM U50,488H for 24 h. In ventricular myocytes incubated for 24 h with 1 microM U50,488H together with 1 microM chelerythrine or 1 microM GF109203X, PKC inhibitors, or 0.1 microM epsilonV1-2 peptide, a selective inhibitor of PKC-epsilon, 30 microM U50,488H still produced the inhibitory effect on the electrically-induced [Ca(2+)](i) transient as it did in naïve ventricular myocytes. Chronic treatment of ventricular myocytes with U50,488H and chelerythrine also attenuated the development of tolerance to acute U50,488H on cyclic AMP accumulation. Cells exposed to chelerythrine, GF109203X, or epsilonV1-2 peptide alone did not show an altered [Ca(2+)](i) response to U50,488H. These results indicate that activation of PKC-epsilon is a critical step in the development of tolerance in the kappa-OR.
authors.affiliation: Department of Physiology and Institute of Cardiovascular Science and Medicine, Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Jing-Jun
authors.initials: JJ
authors.lastname: Zhou
authors.forename: Jin-Song
authors.initials: JS
authors.lastname: Bian
authors.forename: Jian-Ming
authors.initials: JM
authors.lastname: Pei
authors.forename: Song
authors.initials: S
authors.lastname: Wu
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Li
authors.forename: Tak-Ming
authors.initials: TM
authors.lastname: Wong
mesh_terms: D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer / Q000494:pharmacology*; D000470:Alkaloids; D018712:Analgesics, Non-Narcotic / Q000494:pharmacology*; D000818:Animals; D053119:Benzophenanthridines; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism; D004347:Drug Interactions; D004361:Drug Tolerance; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006352:Heart Ventricles / Q000187:drug effects / Q000378:metabolism; D015151:Immunoblotting; D066298:In Vitro Techniques; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D008301:Maleimides / Q000494:pharmacology; D009206:Myocardium / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D010617:Phenanthridines / Q000494:pharmacology; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D051744:Protein Kinase C-epsilon / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017473:Receptors, Opioid, kappa / Q000378:metabolism*
chemical_list: D000470:Alkaloids; D018712:Analgesics, Non-Narcotic; D053119:Benzophenanthridines; D004791:Enzyme Inhibitors; D007211:Indoles; D007527:Isoenzymes; D008301:Maleimides; D010446:Peptide Fragments; D010617:Phenanthridines; D010975:Platelet Aggregation Inhibitors; D017473:Receptors, Opioid, kappa; C448318:epsilonV1-2 peptide; D005576:Colforsin; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000242:Cyclic AMP; C016299:chelerythrine; C497257:Prkce protein, rat; D051744:Protein Kinase C-epsilon; C070515:bisindolylmaleimide I; D002118:Calcium