Tang L, Taylor P B
Department of Biological Sciences, University of Windsor, Ontario, Canada.
J Hypertens. 1996 Jun;14(6):751-7. doi: 10.1097/00004872-199606000-00011.
To study the calcium-dependent mechanisms contributing to altered contractile function in isoproterenol-induced ventricular hypertrophy of the rat heart.
The force-interval relationship, systemic evaluation of changed contractile force and calcium sensitivity of the myofilaments were investigated using small trabecular muscle from hearts with isoproterenol-induced cardiac hypertrophy.
Cardiac hypertrophy was induced by daily subcutaneous injection of isoproterenol for 12 days. The calcium sensitivity of myofilaments was studied using non-ionic detergent (Triton-X-100)-skinned trabeculae. The contractile force was evaluated at various concentrations of extracellular calcium and muscle lengths. The force-interval relationship was used to reflect altered intracellular calcium handling.
The isoproterenol-induced cardiac hypertrophy was associated with significantly enhanced contractile force at various concentrations of extracellular calcium and muscle lengths. Also, an amplified force-interval relationship in hypertrophied muscle at long rest intervals was found. However, this study revealed no change in calcium sensitivity of myofilaments.
Altered intracellullar calcium handling contributes to enhanced contractile force in isoproterenol-induced cardiac hypertrophy.
研究钙依赖机制在异丙肾上腺素诱导的大鼠心脏心室肥厚中对收缩功能改变的作用。
使用异丙肾上腺素诱导心脏肥厚的心脏中的小梁肌，研究力-间期关系、收缩力变化的系统评估以及肌丝的钙敏感性。
通过每日皮下注射异丙肾上腺素12天诱导心脏肥厚。使用非离子去污剂（Triton-X-100）透皮小梁研究肌丝的钙敏感性。在不同细胞外钙浓度和肌肉长度下评估收缩力。力-间期关系用于反映细胞内钙处理的改变。
异丙肾上腺素诱导的心脏肥厚与不同细胞外钙浓度和肌肉长度下收缩力显著增强有关。此外，在长休息间期发现肥厚肌肉中的力-间期关系放大。然而，本研究未发现肌丝钙敏感性的变化。
细胞内钙处理的改变有助于异丙肾上腺素诱导的心脏肥厚中收缩力增强。
