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  • 1
    Electronic Resource
    Electronic Resource
    ETB-mediated contraction differs between left descending coronary artery and its next branch (1999)
    Springer
    Molecular and cellular biochemistry 201 (1999), S. 99-103 
    Details
    ISSN: 1573-4919
    Keywords: endothelin-1 (ET-1) ; Ca2+-ETA receptor ; ETB receptor ; smooth muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Pig left descending coronary artery (main artery) and its next branch (branch arteries) differ in many properties. Here we report on the receptor types and the Ca2+ pools utilized for endothelin (ET) contraction in 3 mm long de-endothelialized rings of the main (weight 7.38 ± 0.38 mg) and the branch (1.07 ± 0.03 mg) arteries. KCl (60 mM) contracted the main and the branch arteries with force of 41.8 ± 3.1 and 16.9 ± 1.0 mN (millinewton), respectively. Force of contraction for all the other agents was normalized taking the KCl value as 100%. We determined the total ET-induced responses using ET-1 and those mediated by ETB using IRL1620. In Ca2+-containing solutions, ET-1 contracted the main arteries with pECB = 8.2 ± 0.1 and a maximum force of 98 ± 5%. The branch arteries also gave similar values of pEC50 (8.4 ± 0.1) and maximum force (99 ± 14%). IRL1620 contracted the main and the branch arteries with pEC50 = 7.9 ± 0.1 but the maximum force was significantly higher in the branch arteries (44 ± 3%) than in the main (15 ± 2%). In Ca2+-free solutions, the pEC50 values for ET-1 or IRL-1620 did not change but the maximum force of contraction was diminished considerably in both main and branch arteries. Thus, the left coronary artery and its next branch differ in that the role of ETB receptors is greater in the latter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007060401412
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Effects of peroxide on contractility of coronary artery rings of different sizes (1999)
    Springer
    Molecular and cellular biochemistry 194 (1999), S. 159-164 
    Details
    ISSN: 1573-4919
    Keywords: free radicals ; ischemia-reperfusion ; sarcoplasmic reticulum ; Ca2+-Mg2+-ATPase ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Reactive oxygen species (ROS, free radicals) produced during cardiac ischemia and reperfusion can damage the contractile functions of arteries. The sarcoplasmic reticulum (SR) Ca2+ pump in coronary artery smooth muscle is very sensitive to ROS. Here we show that contractions of de-endothelialized rings from porcine left coronary artery produced by the hormone Angiotensin II and by the SR Ca2+ pump inhibitors cyclopiazonic acid and thapsigargin correlate negatively with the tissue weight. In contrast, the contractions due to membrane depolarization by high KCl correlate positively. Peroxide also produces a small contraction which correlates negatively with the tissue weight. When artery rings are treated with peroxide and washed, their ability to contract with Angiotensin II, cyclopiazonic acid and thapsigargin decreases. Thus, the SR Ca2+ pump may play a more important role in the contractility of the smaller segments of the coronary artery than in the larger segments. These results are consistent with the hypothesis that ROS which damage the SR Ca2+ pump affect the contractile function of the distal segments more adversely than of the proximal segments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006902603056
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of peroxide on endothelial nitric oxide synthase in coronary arteries (1998)
    Springer
    Molecular and cellular biochemistry 183 (1998), S. 147-152 
    Details
    ISSN: 1573-4919
    Keywords: free radicals ; ischemia-reperfusion ; endothelium ; smooth muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Reactive oxygen species (ROS) are produced in ischemia and reperfusion. Since endothelial nitric oxide synthase (eNOS) is key to the endothelium- dependent vasodilation, we examined the effects of peroxide on this enzyme. We treated cells cultured from pig coronary artery endothelium with different concentrations of hydrogen peroxide, washed them, solubilized them and measured NOS activity by arginine to citrulline conversion. Hydrogen peroxide inhibited the eNOS activity with an IC50 value of 0.85 ± 0.39 mM. In another experiment, we perfused arteries with solutions containing 0 or 1 mM hydrogen peroxide, washed them, removed the endothelium using a cotton swab, centrifuged and solubilized the endothelium and monitored its NOS activity. Hydrogen peroxide (1 mM) did not affect the NOS activity significantly (p 〉 0.05) in this assay. We conclude that the inactivation of eNOS by hydrogen peroxide does not play a major role in the ischemia- reperfusion damage because the peroxide concentrations attained during ischemia-perfusion are much lower than those affecting the eNOS activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006828205261
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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