Calcium uptake by sarcoplasmic reticulum isolated from hearts of septic rats
Myocardial sarcoplasmic reticulum (SR) plays a critical role in the regulation of the cytosolic calcium fluctuations that occur during the cardiac cycle. One function of the SR is to lower the calcium concentration so that myocardial relaxation and thus ventricular filling can occur. The aim of the present study was to determine if hyperdynamic sepsis induced a decrease in the capacity of SR to take up calcium. This defect would result in decreased ventricular filling and thus decreased cardiac output, as has previously been shown in isolated perfused working hearts removed from septic rats. Therefore, rats were anesthetized with ether, and sepsis was induced by the injection of an aliquot of a fecal homogenate into the peritoneal cavity. Control animals either underwent surgery and received an aliquot of sterilized fecal inoculum (sham) or were untreated (no surgery). On day 2 after surgery, animals were anesthetized with pentobarbital, and hearts were removed, weighted, and SR isolated. The rate of uptake of /sup 45/Ca/sup 2 +/ by SR from septic rats was not depressed compared to controls but in fact was elevated. Maximum /sup 45/Ca/sup 2 +/ accumulated by the SR and Ca/sup 2 +/-stimulated ATPase activity were similar in SR from control and septic hearts. These results suggest that the contractile dysfunction noted in the myocardium in early sepsis is probably not due to inadequate SR removal of Ca/sup 2 +/ during diastole.
- Research Organization:
- Louisiana State Univ. Medical Center, New Orleans (USA)
- OSTI ID:
- 6542080
- Journal Information:
- Circ. Shock; (United States), Vol. 25:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALCIUM
UPTAKE
SARCOPLASMIC RETICULUM
BIOLOGICAL FUNCTIONS
SEPTICEMIA
PATHOGENESIS
ATP
ATP-ASE
CALCIUM 45
MYOCARDIUM
RATS
TRACER TECHNIQUES
ACID ANHYDRASES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CALCIUM ISOTOPES
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
ELEMENTS
ENZYMES
EVEN-ODD NUCLEI
FUNCTIONS
HEART
HYDROLASES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
METALS
MUSCLES
NUCLEI
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PHOSPHOHYDROLASES
RADIOISOTOPES
RODENTS
VERTEBRATES
550901* - Pathology- Tracer Techniques