Sympathetic activation after two weeks of nifedipine treatment in primary Raynaud's patients and controls.

The effect of a standardized cold pressor test on circulating noradrenaline and neuropeptide-Y-like immunoreactivity was investigated in 12 women with primary Raynaud's phenomenon and 12 healthy female controls before and after 2 weeks of treatment with the calcium antagonist, nifedipine. Measurement before treatment showed significant increase during the cold pressor test on circulating noradrenaline in both the primary Raynaud's phenomenon group and in the control group (from 0.29 +/- 0.15 ng/ml to 0.33 +/- 0.16 ng/ml, p < 0.05, and from 0.21 +/- 0.14 ng/ml to 0.29 +/- 0.16 ng/ml, p < 0.005, respectively). However, treatment with nifedipine resulted in significantly increased levels of circulating noradrenaline during the cold pressor test only in the control group (from 0.43 +/- 0.21 ng/ml to 0.50 +/- 0.20 ng/ml, p < 0.01). Plasma concentrations of neuropeptide-Y-like immunoreactivity were unchanged by the standardized cold pressor test, whether performed before or during nifedipine treatment in both groups. Nifedipine treatment per se significantly increased circulating noradrenaline in both the primary Raynaud's phenomenon patient group and in the control group (from 0.29 +/- 0.15 to 0.49 +/- 0.13 and 0.21 +/- 0.14 to 0.43 +/- 0.21 ng/ml, respectively, p < 0.001). Similarly, the circulating neuropeptide-Y-like immunoreactivity significantly increased in both the primary Raynaud's phenomenon group and in the control group (from 105 +/- 21 to 137 +/- 19 pmol/l and 107 +/- 17 to 147 +/- 13 pmol/l, respectively, p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)