Neuropeptide Y and nitrite levels in preeclamptic and normotensive gravid women

OBJECTIVES: Vascular tone is controlled largely by the sympathetic nervous system and is modulated by neuropeptide Y. Preeclampsia is linked to sympathetic overactivity. Nitric oxide can cause vasorelaxation of vessels or decrease sympathetic outflow by activating the baroreceptor reflex. Our purpose in this study was to compare serum levels of neuropeptide Y and nitrite levels in normotensive and preeclamptic gravid women. STUDY DESIGN: Twelve preeclamptic and 12 normotensive women matched for race, body mass index, parity, and gestational age were studied. Neuropeptide Y was measured by using a commercial radioimmunoassay. Nitric oxide was converted to nitrite by using metallic cadmium, and nitrite levels were determined spectrophotometrically by using a colorimetric assay. Data are presented as mean +/- SEM and were compared by using a t test. RESULTS: Neuropeptide Y levels were similar among preeclamptic and normotensive gravid women (33.8 +/- 3.0 and 32.2 +/- 3 pg/mL, respectively). Similarly, there were no differences in nitrite concentrations between preeclamptic and normotensive patients (11.6 +/- 0.8 vs 11.2 +/- 0.4 mu mol/L, respectively). We also examined the ratios of neuropeptide Y and nitrite and found no correlation between preeclamptic and normotensive women. CONCLUSION: Peripheral levels of neuropeptide Y or nitrite do not correlate with preeclampsia. Assessment of sympathetic overactivity in preeclampsia requires an alternate model.