Effect of Magnesium Sulfate Infusion on Circulating Levels of Noradrenaline and Neuropeptide-Y-Like Immunoreactivity in Patients with Primary Raynaud's Phenomenon

Abstract

The effect of a short-term magnesium sulfate (MgSO4) infusion on venous plasma concentration of noradrenaline (NA) and neuropeptide-Y-like immunoreactivity (NPY-LI) was investigated in 12 women with primary Raynaud's phenomenon (PRP) and in 12 healthy matched controls. The Raynaud's patients did not demonstrate any significant changes in mean basal plasma NA concentration (0.29 +/- 0.15 vs 0.37 +/- 0.09 ng/mL, ns) after MgSO4 infusion. However, in the controls there was more than twice the amount of circulating noradrenaline (cNA) (0.21 +/- 0.14 vs 0.54 +/- 0.22 ng/mL, P < 0.001) after MgSO4 infusion, compared with the preinfusion value. Measurements during the cold pressor test prior to the MgSO4 infusion showed a significant increase of cNA in both the PRP group and the control group (from 0.29 +/- 0.15 to 0.33 +/- 0.16 ng/mL, P < 0.05, and from 0.21 +/- 0.14 to 0.29 +/- 0.16 ng/mL, P < 0.005, respectively). After MgSO4 infusion the levels of cNA during the cold pressor test increased significantly only in the PRP group (from 0.37 +/- 0.09 to 0.41 +/- 0.11 ng/mL, P < 0.05). Circulating NPY-LI concentrations increased significantly during MgSO4 infusion in the Raynaud's patients as well as in the controls from 105 +/- 21 to 127 +/- 23 pmol/L, P < 0.05, and from 107 +/- 17 to 132 +/- 27 pmol/L, P < 0.01, respectively. There were no detectable changes during the cold pressor tests in either group.(ABSTRACT TRUNCATED AT 250 WORDS)