Abstract: comparative studies have been carried out both for myocardium ultrastrueture, some seroenzyme activities and physiological parameters in Marmota himalayana (2200m and 3300m above sea leve1)and in Hilltop Sprague-Dowley rats (brought from the lowland
to 3300m)．
The investigation showed that levels of RBC，Hb，Hat，TVW／BW ，RVW ／LVW ，MAP，MRVP and the activities of CK，LDH in SD rats were increased and cardiachypertrophy occured，evident ultrastructura1 damnges of myocardium were noticed as well during hypoxia．Ultrastructural change involved edema of intra-and extracellular space，disruptive coagulation bands of myofibrils，disarrangement and disruption 0f filaments，dilatation of endoplasmic reticulum ．swelling of mitochondria，and reduction of glycogen granules．
Therefore，the mechanisms of acc1imatization to hypoxia are different between the two animals．In M .himalayana，an appropriate activation of blood-circulative function is used to adapting the lower 0₂content；while in SD rat，the activation of blood
-forming function isthe main form of adaptation．

Key words: Marmota himalayana, Hilltopsprague-dowley rat, Mocardium, Creatine kinase, Laetate dehydrogenase, Ultrastrueture

摘要： 本文应用生理学与生化酶测定法以及透封电镜结合扫描电镜技术，观察了海拔3300米地区喜马拉雅旱獭心血管的某些生理。生化与超微结构的特点，并与缺氧敏感大鼠进行对比。结
果表明，喜马拉雅早獭的红细胞数、血红蛋白浓度、红细胞压积、颈动脉压、右心室压，心脏占体重百分比、右／左心室比值、肌酸激酶、乳酸脱氢酶等数值以及心肌细胞超微结构均
正常。而由平原进入高原的缺氧敏感大鼠的相应生理参数与血清酶活力则明显升高，心肌细胞超微结构呈现缺氧损害，主要表现为细胞内外水肿，肌节分带模糊不清，肌丝稀巯断裂，肌浆网扩张，线粒体肿胀，糖原颗粒减少。证明在高原土生土长的喜马拉雅早獭对高原低氧有较强的适应能力。

关键词: 喜马拉雅旱獭, 缺氧敏感大鼠, 心肌, 肌酸激酶, 乳酸脱氧酶, 超微结构