J Korean Med Sci.  1996 Jun;11(3):250-257. 10.3346/jkms.1996.11.3.250.

Effects of calcium antagonists on contractions of chorionic arteries in normal and preeclampsia placenta

• Kook H
• Yoon YD
• Baik YH

• KMID: 644958
• DOI: http://doi.org/10.3346/jkms.1996.11.3.250

Abstract

This study was undertaken to observe the effects of organic or inorganic calcium antagonists and to investigate the involvement of cyclic nucleotides in regulating the vascular tone in the chorionic artery from normal or preeclamptic placenta. KCI and prostaglandin (PG) F2 alpha produced marked and constant contractions in chorionic arterial preparations of both normal and preeclamptic placentas. Nifedipine (NIF), verapamil (VER) and diltiazem (DIL) reduced the tension that had been produced by KCI and PGF2 alpha in a concentration-dependent fashion in both preparations, and the potency order of the three agents was NIF> VER > DIL. In preeclamptic arteries, however, the magnitudes of vasodilatation induced by NIF and DIL were much smaller than those in normal chorionic arteries. Mg2+ and Cd2+ also relaxed the tension induced by KCI and PGF2 alpha. In preeclamptic chorionic artery, the vasodilatation induced by Mg2+ was significantly potentiated, while that by Cd2+ was not. Removing endothelium did not alter cyclic GMP content in both preparations. In both preparations contracted by PGF2 alpha, nitroprusside markedly increased cyclic GMP content, but neither cyclic GMP nor cyclic AMP content was affected by acetylcholine, NIF, isopro-terenol, or Mg2+. The above results suggest that neither cyclic AMP nor cyclic GMP is involved in regulating the vascular tone of chorionic artery and that sensitivity of the artery in preeclampsia to the inhibitory action of calcium antagonist might be different from that in normal placenta.

Keyword

Preeclampsia; Chorionic artery; Calcium channel antagonist; Endothelium; Cyclic GMP; Cyclic AMP

MeSH Terms

Arteries/physiopathology
Calcium Channel Blockers/*pharmacology
Cyclic AMP/analysis
Cyclic GMP/analysis
Dinoprost/pharmacology
Female
Human
Placenta/*blood supply
Potassium Chloride/pharmacology
Pre-Eclampsia/*physiopathology
Pregnancy
Vasoconstriction/*drug effects