本文观察了急慢性热暴露后培养乳鼠心肌细胞钙内流、钙调素（ＣａＭ）及Ｃａ￣（２＋）－ＡＴＰ酶活性的变化。结果表明：热暴露后Ｃａ￣（２＋）跨心肌细胞肌膜内流增加，细胞匀浆Ｃａ￣（２＋）－ＡＴＰ酶活性具有下降趋势，活性ＣａＭ含量下降，致心肌细胞内游离钙浓度升高。提示：热暴露后心肌细胞钙稳态发生改变，并可能是心肌细胞损伤的重要原因之一。慢性热暴露后心肌细胞对热损害的反应性有所降低、适应性有所增强。 This article investigates the changes of calcium influx, CaM and Ca ~ (2 +) - ATPase activity in neonatal rat cardiomyocytes cultured in acute and chronic heat exposure. The results showed that the intracellular Ca ~ (2+) influx in myocardial cells increased after heat exposure, the activity of Ca ~ (2 +) - ATPase in the cell homogenate decreased, the content of active CaM decreased and the intracellular free calcium concentration increased . Hint: Myocardial cell calcium homeostasis changes after heat exposure, and may be one of the important reasons of myocardial cell injury. Myocardial cells after heat exposure to chronic heat damage to reduce the reactivity, flexibility has increased.