Effect of Ca2+ agonist Bay K 8644 in human placental arteries

1. Bay K 8644 (0.1 microM induced weak contractions in human placental artery segments that were increased in the presence of 7.5 mM K+. K+ and serotonin (5-HT) induced contractions that were enhanced by preincubation of segments with Bay K 8644. These enhancements were reduced by nifedipine (0.1 mi...

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Bibliographic Details
Published in:General pharmacology 1995-09, Vol.26 (5), p.989-996
Main Authors: BARRUS, M. T, REVIRIEGO, J, MARIN, J
Format: Article
Language:English
Subjects:
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester - pharmacology
Arteries - drug effects
Arteries - metabolism
Biological and medical sciences
Calcium - metabolism
Calcium Channel Agonists - pharmacology
Calcium Channel Blockers - pharmacology
Calcium Radioisotopes
Cardiovascular system
Female
Humans
In Vitro Techniques
Isometric Contraction - drug effects
Medical sciences
Miscellaneous
Muscle Contraction - drug effects
Muscle, Smooth, Vascular - drug effects
Muscle, Smooth, Vascular - metabolism
Pharmacology. Drug treatments
Placenta - blood supply
Placenta - drug effects
Placenta - metabolism
Potassium - pharmacology
Pregnancy
Regional Blood Flow - drug effects
Serotonin - metabolism
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Summary:1. Bay K 8644 (0.1 microM induced weak contractions in human placental artery segments that were increased in the presence of 7.5 mM K+. K+ and serotonin (5-HT) induced contractions that were enhanced by preincubation of segments with Bay K 8644. These enhancements were reduced by nifedipine (0.1 microM) and diltiazem (1 microM). 2. Bay K 8644 induced a 45Ca2+ uptake increase which was potentiated by depolarization with K+ (less than 30 mM) and antagonized by nifedipine. K+ (15 and 30 mM) and 5-HT (1 microM) induced 45Ca2+ uptake that was enhanced by Bay K 8644. 3. These results suggest that Bay K 8644: (1) is unable to activate the quiescent potential-operated Ca2+ channels (POCs) of these arteries, and (2) activates receptor (5-HT)-operated Ca2+ channels or facilitates Ca2+ influx through POCs activated by 5-HT.
ISSN:0306-3623
1879-0011
DOI:10.1016/0306-3623(94)00289-Y