Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Contractile proteins  (1)
  • Force development  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Contractile properties of skinned preparations from ischaemic canine myocardium and coronary arteries (1993)
    Springer
    Pflügers Archiv 425 (1993), S. 82-89 
    Details
    ISSN: 1432-2013
    Keywords: Myocardial ischaemia ; Myocardium ; Vascular smooth muscle ; Dog ; Contractile proteins ; Calcium dependence ; Myosin phosphorylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The influence of prolonged ischaemia on the regulation of contraction in the myocardium and in the smooth muscle of coronary arteries was investigated. Chemically skinned preparations were used which enabled the contraction to be studied with the environment of the contractile filaments controlled. Myocardial ischaemia was produced in anaesthetized adult beagle dogs by occlusion of the left anterior descending artery for 3 h and followed by 30 min reperfusion. Myocardial tissue and segments from coronary arteries were obtained from the ischaemic infarcted wall region (“in vivo ischaemic”) and compared with control preparations from perfused coronary arteries and from the free wall of the left ventricle. Coronary and myocardial preparations were also obtained from the heart after a 3 h period in vitro under anoxic conditions at 37°C (“in vitro ischaemic”) simulating a state of extreme ischaemia. Control myocardial fibres were fully relaxed at pCa (-log-[Ca2+]) 9 and developed 24±5% (n=7) of maximum force at intermediate calcium concentration (pCa 5.5). In contrast, the in vivo and in vitro ischaemic preparations produced force at pCa 9 (28±13 and 39±8%, respectively, n=5 and 7) and showed an increased force development at pCa 5.5 (53±11 and 75±5%). The in vivo and in vitro ischaemic coronary arteries relaxed more slowly following calcium removal than control vessels. The in vitro ischaemic vascular preparations developed active force at pCa 9 and showed increased levels of myosin light chain phosphorylation and reduced phosphatase activity. This suggests a reduced rate of dephosphorylation as a cause for the changes in contracile behaviour of the smooth muscle. In conclusion, extreme ischaemia in vitro is associated with a loss of calcium regulation and an increased calcium sensitivity of the contractile system in myocardium and changes in the phosphorylation/dephosphorylation reactions of coronary arteries. The changes in myocardium appear to occur also during ischaemia in vivo, and might contribute to contracture development in cells under conditions when adenosine triphosphate synthesis is reestablished after reperfusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00374507
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Correlation between isoform composition of the 17 kDa myosin light chain and maximal shortening velocity in smooth muscle (1991)
    Springer
    Pflügers Archiv 418 (1991), S. 523-530 
    Details
    ISSN: 1432-2013
    Keywords: Smooth muscle ; Myosin 17 kDa light chains ; Shortening velocity ; Caged-ATP ; Force development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The relation between the isoform distribution of the myosin 17 kDa essential light chain (LC17) and the mechanical properties of smooth muscle was investigated. The relative content of the basic (LC17b) and acidic (LC17a) isoelectric variants of the 17 kDa myosin light chain was determined in different mammalian smooth muscle tissues. The relative content of LC17b varied between muscles: rabbit rectococcygeus 0%, rabbit trachea 5%, guinea-pig taenia coli 21%, rat uterus 38%, rabbit aorta 56% and rat aorta 60%. The rate of tension development was determined following photolysis of cagedadenosine triphosphate (ATP) in skinned fibres activated with thiophosphorylation of the regulatory light chains. The half-time for force development was 0.67 s in rabbit rectococcygeus, 1.6 s in rabbit trachea, 1.13 s in guineapig taenia coli and 1.38 s in rabbit aorta. The maximal shortening velocity (v max) was determined with the isotonic quick release technique in skinned fibre preparations activated with thiophosphorylation. v max was 0.25 muscle lengths per second (ML/s) in rabbit rectococcygeus, 0.24 ML/s in rabbit trachea, 0.17 ML/s in guinea-pig taenia coli, 0.11 ML/s in rat uterus and 0.03 ML/s in rabbit aorta. The range of variation in v max between muscles was larger than in the half-time for force development. The inverse relationship between v max and the relative content of LC17b in the investigated muscles suggests that the type of essential myosin light chain influences the v max in smooth muscle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00370566
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...