Decreased auxotonic sarcomere shortening in hypertrophied rabbit myocardium
| Autor: | B. B. Hamrell, P. B. Hultgren |
|---|---|
| Rok vydání: | 1985 |
| Předmět: |
Male
Sarcomeres medicine.medical_specialty Physiology Hemodynamics Cardiomegaly Isometric exercise Sarcomere Muscle hypertrophy Physiology (medical) medicine.artery Internal medicine medicine Animals Pressure overload Chemistry Myocardium Cardiac muscle Heart Anatomy Adaptation Physiological Myocardial Contraction medicine.anatomical_structure Pulmonary artery Cardiology Rabbits Stress Mechanical Right Ventricular Free Wall Cardiology and Cardiovascular Medicine |
| Zdroj: | The American journal of physiology. 249(4 Pt 2) |
| ISSN: | 0002-9513 |
| Popis: | Auxotonic sarcomere length change occurs during isometric twitches of isolated cardiac muscle preparations. To assess the amount of internal work in hypertrophied myocardium, we measured auxotonic sarcomere length change during isometric tension development over a range of initial muscle and sarcomere lengths. Hypertrophy was produced by banding the pulmonary artery, which resulted in an increase in the ratio of right ventricular free wall weight to total ventricular weight (normal 0.19 +/- 0.004; hypertrophy 0.35 +/- 0.008; P less than 0.001). Right ventricular free wall trabeculae and papillary muscles were studied with optical and mechanical instrumentation, including a helium-neon laser, to measure sarcomere length and isometric twitch parameters. The resting sarcomere length-resting tension relationship was shifted to the left of normal in the hypertrophied preparations (P less than 0.001). The relationship of sarcomere length at the peak of the twitch with total tension at the same instant was shifted downward and to the right of normal in hypertrophy (P less than 0.01). For the same amount of total tension development there was less than normal sarcomere shortening in the hypertrophied preparations (P less than 0.001). Consequently, there is less than normal work per sarcomere during auxotonic sarcomere shortening in hypertrophied heart muscle. Less sarcomere work for a particular functional state is important to consider in the assessment of the basis of myocardial function in compensated pressure overload hypertrophy. |
| Databáze: | OpenAIRE |
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