OBJECTIVES: Vascular tone is controlled largely by the sympathetic nervous
system and is modulated by neuropeptide Y. Preeclampsia is linked to sympat
hetic overactivity. Nitric oxide can cause vasorelaxation of vessels or dec
rease sympathetic outflow by activating the baroreceptor reflex. Our purpos
e in this study was to compare serum levels of neuropeptide Y and nitrite l
evels in normotensive and preeclamptic gravid women.
STUDY DESIGN: Twelve preeclamptic and 12 normotensive women matched for rac
e, body mass index, parity, and gestational age were studied. Neuropeptide
Y was measured by using a commercial radioimmunoassay. Nitric oxide was con
verted to nitrite by using metallic cadmium, and nitrite levels were determ
ined spectrophotometrically by using a colorimetric assay. Data are present
ed as mean +/- SEM and were compared by using a t test.
RESULTS: Neuropeptide Y levels were similar among preeclamptic and normoten
sive gravid women (33.8 +/- 3.0 and 32.2 +/- 3 pg/mL, respectively). Simila
rly, there were no differences in nitrite concentrations between preeclampt
ic and normotensive patients (11.6 +/- 0.8 vs 11.2 +/- 0.4 mu mol/L, respec
tively). We also examined the ratios of neuropeptide Y and nitrite and foun
d 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.