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Coupling of the Cloned μ‐Opioid Receptor with the ω‐Conotoxin‐Sensitive Ca 2+ Current in NG108‐15 Cells
Author(s) -
Morikawa Hitoshi,
Fukuda Kazuhiko,
Kato Shigehisa,
Mori Kenjiro,
Higashida Haruhiro
Publication year - 1995
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1995.65031403.x
Subject(s) - pertussis toxin , agonist , inverse agonist , chemistry , enkephalin , opioid receptor , patch clamp , receptor , biophysics , endocrinology , microbiology and biotechnology , medicine , g protein , opioid , biology , biochemistry
Voltage‐dependent Ca 2+ currents were measured in NG108‐15 neuroblastoma × glioma hybrid cells transformed to express the rat μ‐opioid receptor by the whole‐cell configuration of the patch‐clamp technique with Ba 2+ as charge carrier. A μ‐opioid receptor‐selective agonist, [ d ‐Ala 2 , N ‐Me‐Phe 4 ,Gly 5 ‐ol]enkephalin caused significant inhibition of voltage‐dependent Ca 2+ currents in μ‐receptor‐transformed NG108‐15 cells but not in nontransfected or vector‐transformed control cells. On the other hand, a δ‐opioid receptor‐selective agonist, [ d ‐penicillamine 2 , d ‐penicillamine 5 ]enkephalin, induced inhibition of voltage‐dependent Ca 2+ currents in both control and μ‐receptor‐transformed cells, which is mediated by the δ‐opioid receptor expressed endogenously in NG108‐15 cells. The inhibition of voltage‐dependent Ca 2+ currents induced by [ d ‐Ala 2 , N ‐Me‐Phe 4 ,Gly 5 ‐ol]enkephalin and [ d ‐penicillamine 2 , d ‐penicillamine 5 ]enkephalin was reduced by pretreatment of the cells with pertussis toxin or ω‐conotoxin GVIA. These results indicate that the μ‐opioid receptor expressed from cDNA functionally couples with ω‐conotoxin‐sensitive N‐type Ca 2+ channels through the action of pertussis toxin‐sensitive G proteins in NG108‐15 cells.