大鼠离体乳头肌收缩末期张力-长度关系的曲线性  

THE CURVILINEARITY OF THE END SYSTOLIC TENSION-LENGTH RELATION OF ISOLATED RAT PAPILLARY MUSCLES

作　　者：丁小凌[1] 李云霞[1] 

机构地区：[1]湖南医科大学心血管生理研究室,长沙410078

出　　处：《生理学报》1991年第3期265-271,共7页Acta Physiologica Sinica

基　　金：国家自然科学基金

摘　　要：大鼠离体左室乳头肌固定于最适初长位,逐步递减“后荷”获得一系列等张收缩的张力、长度缩短程度和速度。结果发现:(1)收缩末期张力-长度关系(ESTLR)为指数曲线,回归方程 T=ar^(-bL)-K 拟合的优度明显高于线性方程拟合的优度(P<0.001),其中 a,k 分别代表总张力和静息张力,b 为曲线的弯曲度;(2)在高钙(4mmol/L)或去甲肾上腺素(NE10^(-6)mol/L)作用下,ESTLR 右上移位,a,b 和无张力缩短速度 L_O 均增大(P均<0.01),尤以高钙时的变化更明显,(3)NE 使张力-速度曲线的右上移位比高钙显著。这提示大鼠离体心肌的 ESTLR 呈非线性特征,参数 a,b 及长度轴截距 L_O 对收缩强度的变化敏感,但对收缩速度改变的敏感性可能比经典的力学指标低。A series of isotonic tension,shortening and shortening velocity were obtainedin isolated rat papillary muscles by varying the setpoint force against which themuscle shortened at optimal length.It was found that(1)end systolic tension-length relation(ESTLR)could be described by an exponential equation.T=ae^(-bL)—k,where a and k represent respectively the total tension and the resting ten-sion and b means curved degree and length-axis intercept(L_0)represents maximalshortening.There was a greater correlation index R^2 when fitted with the equa-tion compared with linear regression(P<0.001).(2)High[Ca^(2+)]_0 shifted ESTLRleftward and upward,with increased a,b and maximal shortening L_0,so did nor-epinephrine(NE)but significantly less than high[Ca^(2+)]_0,whereas the changesin rates of shortening and tension rise were greater during NE infusion than duringhigh[Ca^(2+)]_0 infusion.These results indicated that ESTLR was non-linear inisolated myocardium and exponential parameters a,b and L_0 were sensitive tochanges in contractile intensity,but less sensitive to changes in contractilevelocity when compared with indexes of myocardial mechanics.

关 键 词：心室乳头肌 肌肉收缩 张力长度关系 

分 类 号：R331.31[医药卫生—人体生理学]