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: Calcium uptake by sarcoplasmic reticulum is impaired during the hypodynamic phase of sepsis in the rat heart.
    Author: Wu LL, Ji Y, Dong LW, Liu MS.
    Journal: Shock; 2001 Jan; 15(1):49-55. PubMed ID: 11198357.
    Abstract:
    Alterations of the ATP-dependent Ca2+ uptake in the cardiac sarcoplasmic reticulum (SR) during the 2 hemodynamically distinct phases of sepsis were investigated. Sepsis was induced by cecal ligation and puncture (CLP). Control rats were sham-operated. The SR vesicles were isolated by sucrose gradient centrifugation. The results show that the rates of ATP-dependent Ca2+ uptake in the cardiac SR were unaffected during the early hyperdynamic phase, whereas they were decreased by 41-46% (P < 0.01) during the late hypodynamic phase of sepsis. Analysis of the kinetics of Ca2+ transport indicates that during the late phase of sepsis, the Vmax values of Ca2+ pump for ATP and Ca2+ were decreased, whereas the affinities of Ca2+ pump for ATP and Ca2+ were unaffected. Magnesium stimulated, whereas vanadate inhibited the ATP-dependent Ca2+ uptake, but the Mg2+-stimulated and the vanadate-inhibited Ca2+ uptake activities were significantly lower during the late sepsis. Phosphorylation of SR by the cAMP-dependent and the calmodulin-dependent protein kinases stimulated the ATP-dependent Ca2+ uptake in the control and the early septic experiments, whereas it failed to stimulate Ca2+ uptake in the late sepsis. The extent of the phosphorylation-stimulated Ca2+ uptake activities was reduced by 65-69% (P < 0.01) during the early sepsis, and they were completely abolished during the late sepsis. These data indicate that the ATP-dependent Ca2+ uptake in cardiac SR was impaired during the late hypodynamic phase of sepsis. The impaired Ca2+ uptake during late sepsis was associated with a defective phosphorylation of SR proteins. Because the ATP-dependent Ca2+ uptake by cardiac SR plays an important role in the regulation of contraction-relaxation coupling, our findings may contribute to the understanding of the pathogenesis of altered cardiac function during the progression of sepsis.
    [Abstract] [Full Text] [Related] [New Search]