Effects Of Molybdenum, Silicon And Nickel On α1-Adrenoceptor-Induced Constriction Of Rat Isolated Aorta

1. To determine the effects of trace elements on α1-adrenoceptor-mediated vasoconstriction, we studied the effects of molybdenum (Mo), silicon (Si) and nickel (Ni) on vasoconstrictor response to an α1-adrenoceptor agonist in rat aorta. 2. Cumulative concentration–contraction curves were obtained for phenylephrine (1 nmol/L–10 μmol/L) in the absence and presence of Mo, Si and Ni (0.3, 1 and 3 μmol/L) in rat aorta rings. Increasing the concentration of Mo and Si from 0.3 to 3 μmol/L shifted the cumulative concentration–contraction curve to the right, but did not reduce the maximal contractile response to phenylephrine. In contrast, Ni at 1 and 3 μmol/L shifted the cumulative concentration–contraction curve to the right and, at 3 μmol/L, reduced the maximum contractile response to phenylephrine. 3. We conclude that micromolar concentrations of Mo, Si and Ni affected α1-adrenoceptor-induced vasoconstriction and that Ni significantly inhibited the maximal contractile response to phenylephrine in rat isolated aorta.