Neuropeptide Y and noradrenaline in human uterus and myometrium during normal and pre-eclamptic pregnancy

The myometrial levels of noradrenaline (NA) and neuropeptide Y (NPY), a recently discovered neuropeptide that coexists with NA in many sympathetic nerves, have been measured by immunohistochemistry and biochemistry in normal and pre-eclamptic pregnancy and compared with non-pregnant controls. In the non-pregnant uterus there were high levels of NA and NPY and a rich presence of NA/NPY nerves in the myometrium and around blood vessels. In pregnancy both substances were significantly lower as compared with non-pregnant women. Five patients with pre-eclampsia had levels of NA/NPY that were less markedly reduced than in normal pregnant women. The results show that NA and NPY coexist also in human uterine nerves, and that both decrease significantly during pregnancy. Since both substances are vasoactive, the observed reduction might be of physiological importance for normal pregnancy.