Influence of glycosylation inhibitors on dihydropyridine binding to cardiac cells.
In primary cultures of neonatal rat heart cells we found a linear correlation between the number of L-type calcium channel-specific dihydropyridine (DHP) binding sites and spontaneous beating frequency (v). Formation of glycoproteins in tissue culture was suppressed by different inhibitors of N-glycosylation. This inhibition alters to a different extent the binding of the DHP ligand (+)-[methyl-3H]PN 200-110 and v. The most severe but reversible effect occurs at 6 micrograms/ml tunicamycin (Bmax approximately 45% and v approximately 6%, resp., of control), a slight increase in Bmax at 0.1-0.5 mM castanospermine and 0.05-2.5 mM deoxymannojirimycin. The other inhibitors gave no significant alteration of Bmax.
Institute of Biochemistry and Molecular Physiology, University of Potsdam, Berlin, Germany.
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Henning
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Wallukat
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Holtzhauer
D017485:1-Deoxynojirimycin / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D002121:Calcium Channel Blockers / Q000378:metabolism*; D002478:Cells, Cultured; D004095:Dihydropyridines / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006031:Glycosylation / Q000187:drug effects; D006321:Heart / Q000187:drug effects; D007212:Indolizines / Q000494:pharmacology; D009206:Myocardium / Q000378:metabolism*; D051381:Rats; D017026:Swainsonine / Q000494:pharmacology; D014415:Tunicamycin / Q000494:pharmacology; D054836:Indolizidines
D017485:1-Deoxynojirimycin; D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D004791:Enzyme Inhibitors; D007212:Indolizines; D017026:Swainsonine; D014415:Tunicamycin; C038806:1,4-dihydropyridine; C037806:castanospermine; D054836:Indolizidines