title: The calcium-magnesium interaction in the process of release of noradrenaline by nicotine.
abstract: The calcium-magnesium (Ca2+-Mg2+) interaction in the process of nicotine-induced release of [3H]noradrenaline ([3H]NA) from rat isolated vas deferens was studied. Increasing extracellular concentrations of Mg2+ caused a dose-dependent depression of release of [3H]NA by nicotine, and this inhibitory effect of Mg2+ was overcome by raising the concentration of CA2+. It is concluded that Mg2+ antagonizes the nicotine-induced increase in the Ca2+ influx into the adrenergic nerve terminals, and that nicotine acts on adrenergic neuronal membrane rather than intraneuronally to cause release of NA.
mesh_terms: D000320:Adrenergic Fibers / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism*; D051381:Rats; D014649:Vas Deferens / Q000187:drug effects / Q000378:metabolism*
chemical_list: D009538:Nicotine; D008274:Magnesium; D002118:Calcium; D009638:Norepinephrine