Coupling of the cloned mu-opioid receptor with the omega-conotoxin-sensitive Ca2+ current in NG108-15 cells.
Voltage-dependent Ca2+ currents were measured in NG108-15 neuroblastoma x glioma hybrid cells transformed to express the rat mu-opioid receptor by the whole-cell configuration of the patch-clamp technique with Ba2+ as charge carrier. A mu-opioid receptor-selective agonist, [D-Ala2,N-Me-Phe4,Gly5-ol]-enkephalin caused significant inhibition of voltage-dependent Ca2+ currents in mu-receptor-transformed NG108-15 cells but not in nontransfected or vector-transformed control cells. On the other hand, a delta-opioid receptor-selective agonist, [D-penicillamine2,D-penicillamine5]enkephalin, induced inhibition of voltage-dependent Ca2+ currents in both control and mu-receptor-transformed cells, which is mediated by the delta-opioid receptor expressed endogenously in NG108-15 cells. The inhibition of voltage-dependent Ca2+ currents induced by [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin [D-penicillamine2,D-penicillamine5]enkephalin was reduced by pretreatment of the cells with pertussis toxin or omega-contoxin GVIA. These results indicate that the mu-opioid receptor expressed from cDNA functionally couples with omega-contoxin-sensitive N-type Ca2+ channels through the action of pertussis toxin-sensitive G proteins in NG108-15 cells.
Morikawa
H
H
Department of Biophysics, Kanazawa University School of Medicine, Japan.
Fukuda
K
K
Kato
S
S
Mori
K
K
Higashida
H
H
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004553:Electric Conductivity; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D020881:Enkephalin, D-Penicillamine (2,5)-; D004745:Enkephalins / Q000378:metabolism / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology; D015870:Gene Expression; D005910:Glioma; D006822:Hybrid Cells; D009447:Neuroblastoma; D010455:Peptides / Q000494:pharmacology*; D037342:Pertussis Toxin; D051381:Rats; D017450:Receptors, Opioid, mu / Q000235:genetics / Q000502:physiology*; D014162:Transfection; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D020866:omega-Conotoxin GVIA
D015220:Calcium Channels; D018076:DNA, Complementary; D004745:Enkephalins; D010455:Peptides; D017450:Receptors, Opioid, mu; D010566:Virulence Factors, Bordetella; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D020881:Enkephalin, D-Penicillamine (2,5)-; D020866:omega-Conotoxin GVIA; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins