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

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