title: Comparative actions of 1,10-phenanthroline nickel(II) chelates and their constituent metal ion and ligands on the guinea-pig isolated atrium.
abstract: The actions of fully co-ordinated, inert nickel(II) chelates of 1,10-phenanthroline and 3,4,7,8-tetramethyl-1,10-phenanthroline have been compared on the guinea-pig isolated atrium with those of their constituent metal ion and ligands. In general, each test substance showed distinctive actions suggesting that the effects of the metal chelates are mediated by the intact chelate cation and not by liberated metal ion or ligand. Differences in the actions of the unsubstituted and the highly methylated compounds may result from the greater capacity of the methylated chelate and ligand to induce more profound and sustained conformational changes in the responsive atrial pre- and postsynaptic membranes thereby promoting more rapid and prolonged influx of Ca2+.
mesh_terms: D000818:Animals; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism; D009532:Nickel / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism; D010618:Phenanthrolines / Q000494:pharmacology*
chemical_list: D010618:Phenanthrolines; D009532:Nickel; D009638:Norepinephrine