Maturational changes in cardiac muscle myosin adenosine triphosphatase activity relative to hemodynamic alterations in newborn lambs.
We performed a chronologic investigation of left (LV) and right (RV) ventricular myosin ATPase activity and hemodynamics in newborn lambs. We found an elevation in myosin ATPase activity for the LV, which was achieved by 6 to 8 weeks of age and which correlated directly with increasing ventricular stroke work. Myosin ATPase activity did not increase with age for the RV, a finding which was associated with a postnatal decrease in ventricular stroke work. These findings may represent an important postnatal adaptation of newborn myocardium to the demands of extrauterine life.
D000251:Adenosine Triphosphatases / Q000096:biosynthesis*; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D005260:Female; D006321:Heart / Q000502:physiology*; D006352:Heart Ventricles / Q000201:enzymology; D006439:Hemodynamics; D009206:Myocardium / Q000201:enzymology*; D009218:Myosins / Q000378:metabolism*; D049590:Postpartum Period; D011247:Pregnancy; D012756:Sheep; D013318:Stroke Volume
D000251:Adenosine Triphosphatases; D009218:Myosins