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In vitro vascular effects of cicletanine in pregnancy‐induced hypertension
Author(s) -
Ebeigbe A.B.,
Cabanie M.
Publication year - 1991
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1991.tb12365.x
Subject(s) - in vitro , pregnancy , pharmacology , medicine , hypertension in pregnancy , chemistry , preeclampsia , biology , biochemistry , genetics
1 The vascular effects of cicletanine have been studied in vitro on ring preparations of inferior epigastric arteries from normotensive human females and human females with pregnancy‐induced hypertension (preeclampsia). 2 Cicletanine (10 −7 –10 −3 m ) elicited concentration‐dependent relaxation of vessels precontracted with 10 −7 m noradrenaline (NA) or 60 m m K + but was more potent in the former. Relaxation was significantly greater in rings from preeclamptic patients and was uninfluenced by endothelium removal. 3 The intracellular Ca‐dependent contractile responses to 10 −5 m NA in Ca‐free medium as well as the subsequent extracellular Ca‐dependent contractions (on restoration of external Ca) were significantly attenuated dose‐dependently by cicletanine (10 −5 m , 3 × 10 −4 m ) in arterial rings from both normotensive and preeclamptic patients. Cicletanine also relaxed rings precontracted by 25 m m K + but was ineffective against 80 m m K + ‐induced contractions. 4 The inhibition of intracellular Ca‐dependent contractions was significantly greater in rings from preeclamptic than from normotensive patients whereas extracellular Ca‐dependent contractions were comparably inhibited in both groups. Nifedipine, on the other hand, had little effect on the intracellular Ca‐dependent contractions but significantly depressed extracellular Ca‐dependent contractions. 5 Cicletanine‐induced relaxation was uninfluenced by pretreatment with propranolol, ouabain, tetraethylammonium, procaine, indomethacin, cimetidine or tetrodotoxin but was antagonized by glibenclamide. 6 The results show that cicletanine inhibits contractile responses of human isolated inferior epigastric arteries by a mechanism unrelated to endothelial factors but associated with inhibition of calcium metabolism. An action of cicletanine on glibenclamide‐sensitive K + channels is also suggested. Cicletanine‐induced inhibition was significantly greater in arteries from preclamptic patients.