Effects of U46619 on intracellular Ca++ concentration and tension in human umbilical artery.

Abstract

OBJECTIVE The aim was to examine the effects of U46619, a thromboxane A2 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++ concentration 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.

Statistics

0100200300'01'03'05'07'09'11'13'15'17
Citations per Year

103 Citations

Semantic Scholar estimates that this publication has 103 citations based on the available data.

See our FAQ for additional information.

Cite this paper

@article{Toyofuku1995EffectsOU, title={Effects of U46619 on intracellular Ca++ concentration and tension in human umbilical artery.}, author={Kazutomo Toyofuku and Junji Nishimura and Susumu Kobayashi and Hiroshi Nakano and Hideo Kanaide}, journal={American journal of obstetrics and gynecology}, year={1995}, volume={172 5}, pages={1414-21} }