These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Effects of U46619 on intracellular Ca++ concentration and tension in human umbilical artery.
    Author: Toyofuku K, Nishimura J, Kobayashi S, Nakano H, Kanaide H.
    Journal: Am J Obstet Gynecol; 1995 May; 172(5):1414-21. PubMed ID: 7755047.
    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.
    [Abstract] [Full Text] [Related] [New Search]