Morikawa H, Fukuda K, Kato S, Mori K, Higashida H
Department of Biophysics, Kanazawa University School of Medicine, Japan.
J Neurochem. 1995 Sep;65(3):1403-6. doi: 10.1046/j.1471-4159.1995.65031403.x.
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.
采用膜片钳技术的全细胞记录模式，以Ba2+作为载流子，在转染表达大鼠μ阿片受体的NG108-15神经母细胞瘤×胶质瘤杂交细胞中测量电压依赖性Ca2+电流。μ阿片受体选择性激动剂[D-Ala2，N-Me-Phe4，Gly5-ol]脑啡肽可显著抑制转染μ受体的NG108-15细胞中的电压依赖性Ca2+电流，但对未转染或转染载体的对照细胞无此作用。另一方面，δ阿片受体选择性激动剂[D-青霉胺2，D-青霉胺5]脑啡肽可抑制对照细胞和转染μ受体细胞中的电压依赖性Ca2+电流，这是由NG108-15细胞中内源性表达的δ阿片受体介导的。用百日咳毒素或ω-芋螺毒素GVIA预处理细胞后，[D-Ala2，N-Me-Phe4，Gly5-ol]脑啡肽和[D-青霉胺2，D-青霉胺5]脑啡肽诱导的电压依赖性Ca2+电流抑制作用减弱。这些结果表明，在NG108-15细胞中，由cDNA表达的μ阿片受体通过百日咳毒素敏感的G蛋白与ω-芋螺毒素敏感的N型Ca2+通道发生功能性偶联。
