Inhibitory modulation of fast and slow Ca(2+)-currents in neuroblastoma x glioma cells during differentiation.
Mouse neuroblastoma x rat glioma hybrid cells (N x G, 108CC15) were used to study the inhibitory effects of the synthetic opioid D-Ala2-D-Leu5-enkephalin (DADLE), somatostatin, adrenaline-alpha 2 and angiotensin II on voltage-dependent Ca(2+)-currents (ICa) using the patch-clamp technique in the whole-cell configuration mode. The inhibitory effects could be abolished by pretreatment of N x G cells with pertussis toxin or intracellular infusion of GDP beta S indicating an involvement of a pertussis toxin sensitive GTP-binding protein (G-protein), presumably Go. The effect of DADLE, the strongest inhibitor of ICa, was studied during dibutyryl cyclic AMP (dBcAMP) induced differentiation. Using omega-conotoxin GVIA (omega-CTX) and methoxyverapamil (D600) as specific Ca(2+)-channel blockers of the N- and L-type Ca(2+)-channels, it was found that in N x G cells DADLE predominantly induces inhibition of T- and N-type Ca(2+)-channels.
Eckert
R
R
II. Physiologisches Institut der Universität des Saarlandes, Homburg, F.R.G.
Trautwein
W
W
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects*; D002454:Cell Differentiation; D016308:Enkephalin, Leucine-2-Alanine / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology*; D005711:Gallopamil / Q000494:pharmacology; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D006822:Hybrid Cells; D051379:Mice; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology; D010456:Peptides, Cyclic / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology; D051381:Rats; D014407:Tumor Cells, Cultured; D020866:omega-Conotoxin GVIA
D015220:Calcium Channels; D010456:Peptides, Cyclic; D005711:Gallopamil; D016308:Enkephalin, Leucine-2-Alanine; D020866:omega-Conotoxin GVIA; D011493:Protein Kinase C; D019204:GTP-Binding Proteins