Vasorelaxant effect of levcromakalim on isolated umbilical arteries of preeclamptic women.
OBJECTIVE
Potassium channel openers are revealed to be a new type of antihypertensive drug. We aimed to clarify the effects of levcromakalim, an ATP-sensitive potassium channel opener, on human isolated umbilical artery (UA) and to compare them with those of nifedipine and magnesium sulphate, which are currently used in the treatment of preeclampsia (PE).


METHODS
A total of 52 umbilical arteries, isolated immediately after delivery from 27 healthy and 25 preeclamptic pregnant women, were placed into 10-ml organ baths filled with Kreb's solution at physiological pH and temperature. The concentration-dependent relaxations in response to levcromakalim, nifedipine and magnesium sulphate were compared in vessels precontracted with serotonin (1 micromol/l).


RESULTS
The maximal relative relaxation responses (E(max), expressed as percentage of serotonin-induced precontraction) to magnesium sulphate, nifedipine and levcromakalim in umbilical arteries were identical in the healthy (85.06+/-3.31, 84.80+/-3.01 and 80.37+/-5.32%, respectively) and preeclamptic (77.20+/-5.30, 83.36+/-2.37 and 79.13+/-4.30%, respectively) groups.


CONCLUSIONS
Levcromakalim has a vasodilatory effect on the umbilical artery like magnesium sulphate and nifedipine, and serves as an antihypertensive potential that might be used in the treatment of preeclampsia. However, further experimental and clinical studies are needed to propose that ATP-sensitive potassium channel openers are beneficial drugs in cases of clinical preeclampsia.
Polat
Belgin
B
Zekai Tahir Burak Maternity Hospital, Perinatalogy, Ankara, Turkey. belginp@yahoo.com
Tufan
Hale
H
Danisman
Nuri
N
D000328:Adult; D016022:Case-Control Studies; D019806:Cromakalim / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008278:Magnesium Sulfate / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D009543:Nifedipine / Q000494:pharmacology; D011225:Pre-Eclampsia / Q000188:drug therapy; D011247:Pregnancy; D014469:Umbilical Arteries / Q000187:drug effects*; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
D014665:Vasodilator Agents; D019806:Cromakalim; D008278:Magnesium Sulfate; D009543:Nifedipine