Effects of U46619 on intracellular Ca++ concentration and tension in human umbilical artery
| Autor: | Hideo Kanaide, Kazuki Toyofuku, Sei Kobayashi, Junji Nishimura, Hitoo Nakano |
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| Rok vydání: | 1995 |
| Předmět: |
medicine.medical_specialty
Vascular smooth muscle Thromboxane chemistry.chemical_element Calcium In Vitro Techniques Muscle Smooth Vascular Umbilical Arteries Thromboxane A2 Pregnancy medicine.artery Internal medicine medicine Extracellular Humans Vasoconstrictor Agents Fluorometry Analysis of Variance business.industry Obstetrics and Gynecology Umbilical artery Depolarization Prostaglandin Endoperoxides Synthetic Endocrinology Mechanism of action chemistry Vasoconstriction 15-Hydroxy-11 alpha 9 alpha-(epoxymethano)prosta-5 13-dienoic Acid cardiovascular system Biophysics lipids (amino acids peptides and proteins) Female medicine.symptom business Intracellular Muscle Contraction |
| Zdroj: | American journal of obstetrics and gynecology. 172(5) |
| ISSN: | 0002-9378 |
| Popis: | OBJECTIVE: The aim was to examine the effects of U46619, a thromboxane A 2 analog, on intracellular Ca ++ concentration and tension in human umbilical artery. STUDY DESIGN: By means of front-surface fluorometry and human umbilical arterial strips loaded with fura-2 we simultaneously measured intracellular Ca ++ concentration and tension. RESULTS: In the presence of extracellular Ca ++ (1.25 mmol/L), U46619 elevated intracellular Ca ++ concentrations and tension in a concentration-dependent manner. Oscillations of both intracellular Ca ++ concentration and tension were evident in many cases. In the absence of extracellular Ca ++ U46619 induced a transient elevation of intracellular Ca ++ concentration that was associated with a transient increase and a sustained tension. At any given intracellular Ca ++ concentration level the tension induced by the cumulative application of extracellular Ca ++ during depolarization with high external K + in the presence of U46619 was greater than that in the absence of this drug; thus the intracellular Ca ++ concentration-tension relationship in the presence of U46619 shifted to the left. CONCLUSION: The tension developed by U46619 depends both on an influx of Ca ++ from the extracellular space and on release of intracellular Ca ++ , and U46619 increased Ca ++ sensitivity of the contractile apparatus. |
| Databáze: | OpenAIRE |
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