Slo)的Vl/V3比，分别下降38. 9%和61.0%; V-下降8. 3%和13.3%0 (2)高血压肥厚心肌
比值较术前对照S。分别下降84. 4%和93.50o，较同龄假手术对照S。和S1。组也分别低74. 5%和83.30o，而Vm,x则比S。组下降33. 3%和48.3ooe (3) 6组48只大鼠结果相关分析表明，Vmax与V1%高度正相关，与V3%高度负相关。(P均小于0.01)。上述结果提示:高血压肥厚心肌收缩速度明显下降，其主要生化机制似与同功酶谱由V1优势向V3迁移有关。
CHANGES IN MYOSIN ISOENZYMES COMPOSITION AND THE MAXIMUM SHORTENING VELOCITY IN HYPERTROPHIC LEFT VENTRICULAR MUSCLE OF RATS
L1u L1-Q1oNG, L1 YUN-XIA
laboratory of Cardiovascular Physiology，Hunan Medical University Changsha 410078)
Changes in unloaded maximum shortening velocity (Vmax) and myosin isoenzymes (MI) composition of rat left ventricular muscle were examined in the 8一week or 16week Goldblatt hypertensive (H8，His)and hypertension- regressive rats (R8).The Vmax was estimated by extrapolation to zero afterload from the tension-velocity curve of left ventricular papillary muscle，while the Ml composition (VI，V 2 and V 3) was separated by polyacrylamide gel electrophoresis and determined by densitometry. The results showed that:(1)A slow age-dependent shift to V3 and a decrease in VmaX were observed in 16一and 24一week-old rats (S8，Sie)，in which VI/V3 ratio was decreased respectively by 38. 9%and 61.0%and VmaX was decreased respectively by 8. 3%and
13. 3%when compared with that of the 8-week-old rats (So).(2)There was a significant decrease in V1/V3 ratio and VmaX in 8-week (H8) and 1 6一week (H16)hypertension induced hypertrophic left ventricular muscle as evidenced by the fact that the V1/V3 ratio decreased by 84. 4%and 9 3. 5%and Vmax decreased by 33. 3%and 48. 3%in H8 and Hlo as compared with that of the control rats (So).(3)There was a partial recovery in Vm- and V,/V3 ratio in (R8)group rats.(4)The V,ax was positively correlated with the level of V, (r=0. 9215，PLO. 01)and negatively with the level of V3 (r=0. 9071，P<0. 01)as analyzed in all the six experimental groups of a total of 48 rats (So， S8，Sis，Hg，His，R8).In conclusion，a significant shift of the myosin isoenzymes towards low ATPase activity V3 might be the biochemical mechanism response ble，at least in part，for the decrease in maximum shortening velocity in the hypertrophic left ventricular muscle induced by pressure overload.
刘立琼, 李云霞. 大鼠肥厚心肌缩短速度和肌凝蛋白重链同功酶谱的变化[J]. 生理学报 1996; 48 (4): .
L1u L1-Q1oNG, L1 YUN-XIA. CHANGES IN MYOSIN ISOENZYMES COMPOSITION AND THE MAXIMUM SHORTENING VELOCITY IN HYPERTROPHIC LEFT VENTRICULAR MUSCLE OF RATS. Acta Physiol Sin 1996; 48 (4): (in Chinese with English abstract).