Depressed sodium-calcium exchange in human umbilical arteries from women with preeclampsia.
Responses to low-sodium solution were studied in helical preparations of human umbilical arteries from women with preeclampsia and age-matched normotensive women. Reduction of extracellular sodium concentration (replaced by N-methyl-D-glucamine, NMG) and consequent restoration of extracellular sodium-evoked contractions and relaxations, respectively, in the arteries pretreated with phenoxybenzamine, caffeine, ryanodine, and verapamil. The rate and magnitude of the contraction induced by low-sodium solution and the rate of the relaxation induced by the restoration were less in preeclampsia than in normotension. Therefore, the activity of Na-Ca exchange is depressed in human umbilical arterial smooth muscle in preeclampsia, suggesting a possibility that the depressed activity leads to an abnormal regulation of arterial tone in preeclampsia.
D000328:Adult; D001794:Blood Pressure; D002118:Calcium / Q000378:metabolism*; D005260:Female; D006801:Humans; D006830:Hydralazine / Q000494:pharmacology; D011225:Pre-Eclampsia / Q000378:metabolism*; D011247:Pregnancy; D012964:Sodium / Q000378:metabolism*; D014469:Umbilical Arteries / Q000378:metabolism*; D014661:Vasoconstriction / Q000187:drug effects
D006830:Hydralazine; D012964:Sodium; D002118:Calcium