Suppression by [D-Pen2, D-Pen5]enkephalin on cyclic AMP dependent protein kinase-induced, but not protein kinase C-induced increment of intracellular free calcium in NG108-15 cells.
In neuroblastoma X glioma NG108-15 cell lines, KCl 50 mM produced a significant increase in [Ca2+]i which was blocked completely by voltage-dependent Ca2+ channel antagonist verapamil. High K(+)-induced increase in [Ca2+]i can be suppressed by selective delta opioid agonist [D-Pen2, D-Pen5]enkephalin (DPDPE) (an effect completely reversed by opioid antagonist naloxone), but not by the mu agonist ohmefentanyl (OMF) or kappa agonist 66A-078. Aside from high K+ stimulation, a number of chemicals can produce an increase in [Ca2+]i, i.e., selective adenylate cyclase activator forskolin, the membrane permeable cyclic AMP (cAMP) analogue dibutyryl-cAMP (Bt2cAMP) and the activator of protein kinase C (PKC) 12-O-tetradecanoylphorbol 13-acetate (TPA). All these effects can be readily blocked by verapamil. DPDPE blocks the increase in [Ca2+]i induced by forskolin and Bt2cAMP, but not that by TPA. The results suggest that cAMP dependent protein kinase-, but not PKC-induced Ca2+ influx mechanism seems to be involved in the delta receptor mediated opioid effect.
Department of Physiology, Beijing Medical University, P.R. China.
J F
JF
Wang
X J
XJ
Shun
H F
HF
Yang
M F
MF
Ren
J S
JS
Han
D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects; D005576:Colforsin / Q000494:pharmacology; D003864:Depression, Chemical; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000494:pharmacology*; D005910:Glioma / Q000201:enzymology / Q000378:metabolism; D006822:Hybrid Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D007424:Intracellular Fluid / Q000378:metabolism; D051379:Mice; D009447:Neuroblastoma / Q000201:enzymology / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors* / Q000378:metabolism; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D017465:Receptors, Opioid, delta / Q000187:drug effects / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects
D000700:Analgesics; D015220:Calcium Channels; D004745:Enkephalins; D047428:Protein Kinase Inhibitors; D017465:Receptors, Opioid, delta; D005576:Colforsin; D003994:Bucladesine; D011189:Potassium Chloride; D020881:Enkephalin, D-Penicillamine (2,5)-; D011494:Protein Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium