Protein kinase inhibitor potentiates opioid delta-receptor currents in Xenopus oocytes.
In Xenopus oocytes injected with RNA coding for the delta-opioid receptor a small chloride current was evoked by [D-Ala2,Ser5]leucine-enkephaline-Thr6 (DSLET), a delta 2-opioid agonist. The evoked currents were rapidly reduced upon repeated challenges of DSLET. When Gil alpha RNA was co-injected into the oocyte, the evoked currents were increased 3.8-fold and became constant after at least three repeated challenges. In oocytes injected with RNAs coding for delta-receptor and Gil alpha, pretreatment with K-252a, a potent inhibitor of protein kinases, further potentiated the delta-receptor-mediated current responses, compared with those without the inhibitor. These results suggest that signalling involving the delta-opioid receptor is inactivated through in vivo phosphorylation in the Xenopus oocyte.
Department of Pharmacology, Yokohama City University School of Medicine, Japan.
H
H
Ueda
T
T
Miyamae
N
N
Fukushima
Y
Y
Misu
D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D002227:Carbazoles / Q000494:pharmacology; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism*; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism; D026121:Indole Alkaloids; D051379:Mice; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger / Q000378:metabolism / Q000494:pharmacology; D017465:Receptors, Opioid, delta / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D014982:Xenopus laevis
D000700:Analgesics; D002227:Carbazoles; D018118:Chloride Channels; D026121:Indole Alkaloids; D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D017465:Receptors, Opioid, delta; D004743:Enkephalin, Leucine; C034318:enkephalin, Ser(2), Leu(5), Thr(6)-; C049985:staurosporine aglycone; D011493:Protein Kinase C; D019204:GTP-Binding Proteins