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CALCIUM TRANSIENTS IN SINGLE MYOCYTES AND MEMBRANOUS ULTRASTRUCTURES DURING THE DEVELOPMENT OF CARDIAC HYPERTROPHY AND HEART FAILURE IN RATS
Author(s) -
Kuramochi Takehiko,
Honda Masaaki,
Tanaka Koichi,
Enornoto Kohichi,
Hashimoto Michio,
Morioka Shigefumi
Publication year - 1994
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1994.tb02664.x
Subject(s) - medicine , ventricle , calcium , myocyte , endoplasmic reticulum , maladaptation , heart failure , muscle hypertrophy , endocrinology , calcium in biology , right ventricular hypertrophy , pressure overload , cardiology , chemistry , biology , microbiology and biotechnology , cardiac hypertrophy , psychiatry
SUMMARY 1. We examined changes in intracellular calcium transients of separated single myocytes from the right ventricle (RV) of the rat heart during the change from adaptation to maladaptation in response to a pressure overload. 2. Right ventricular hypertrophy (RVH) secondary to pulmonary hypertension was induced by a subcutaneous injection of monocrotaline. Developed tensions of the RV‐free wall were decreased as RVH progressed. Single myocytes were separated from the RV during different stages of RVH. Fura‐2/AM‐loaded cells were field stimulated, and changes in calcium transients were measured by Olympus OSP‐3 system. We also examined membranous ultrastructures (sarcoplasmic reticulum, mitochondria, surface caveolae) involved in calcium metabolism in the hearts using scanning electron microscopy. 3. We observed characteristic changes in calcium transients during the change from adaptation to maladaptation, and also found that one parameter (amplitude) of calcium transients appeared to be correlated with the changes in the number of sarcoplasmic reticulum. 4. These results provided some insights into the mechanism of calcium handling of hypertrophied heart in response to a pressure overload from adaptation to maladaptation especially when stimulatory frequency was high, and suggested that heart rate control is a very important factor for the treatment of patients with congestive heart failure.