胆固醇和类固醇激素对犬及兔脑突触体细胞膜上钙刺激的ATP酶及脂质流动性影响的构效关系

Structure activity relationship of cholesterol and steroid hormones with respect to their effects on the Ca2+-stimulated ATPase and lipid fluidity of synaptosomal plasma membranes from dog and rabbit brain.

Deliconstantinos G

Department of Experimental Physiology, University of Athens Medical School, Greece.

Comp Biochem Physiol B. 1988;89(3):585-94. doi: 10.1016/0305-0491(88)90178-2.

Abstract

Binding of liposomal-[14C]-cholesterol into dog brain synaptosomal plasma membranes (SPM) follows a sigmoid path (Hill coefficient h = 1.96 +/- 0.12). 2. Ca2+-stimulated ATPase activity increased (approx. 95%) at a concentration range (0.1-0.4 mM) of liposomal cholesterol and testosterone (up to 10 microM). While progesterone up to 10 microM decreased the enzyme activity (approx. 70%) in dog and rabbit brain SPM. 3. Fluorescence anisotropy, [(r0/r)-1]-1, of 1,6-diphenyl-1,3,5-hexatriene (DPH) was 1.04 +/- 0.04 in rabbit brain SPM and 1.72 +/- 0.09 in dog brain SPM. 4. Lipid phase separations at 23.5 +/- 1.2 degrees C in dog brain SPM and at 17.2 +/- 0.9 degrees C in rabbit brain SPM were observed. In dog brain SPM it increased to 33.4 +/- 1.8 degrees C, while in rabbit brain SPM was abolished after treatment with liposomal cholesterol. 5. The allosteric inhibition of Ca2+-stimulated ATPase by Na+ ions showed a Hill coefficient h = 1.72 +/- 0.15 and h = 1.48 +/- 0.08 for dog and rabbit brain SPM respectively, which increased to h = 2.83 +/- 0.55 and h = 2.34 +/- 0.35 after treatment with liposomal cholesterol.

摘要

脂质体-[14C]-胆固醇与犬脑突触体细胞膜（SPM）的结合呈S形曲线（希尔系数h = 1.96±0.12）。2. 在脂质体胆固醇和睾酮浓度范围（0.1 - 0.4 mM）（睾酮高达10 microM）时，Ca2+刺激的ATP酶活性增加（约95%）。而高达10 microM的孕酮会使犬和兔脑SPM中的该酶活性降低（约70%）。3. 1,6 - 二苯基 - 1,3,5 - 己三烯（DPH）的荧光各向异性，[(r0/r)-1]-1，在兔脑SPM中为1.04±0.04，在犬脑SPM中为1.72±0.09。4. 在23.5±1.2℃观察到犬脑SPM的脂质相分离，在17.2±0.9℃观察到兔脑SPM的脂质相分离。在犬脑SPM中，该温度升至33.4±1.8℃，而在兔脑SPM中，用脂质体胆固醇处理后脂质相分离消失。5. Na+离子对Ca2+刺激的ATP酶的变构抑制在犬和兔脑SPM中分别显示希尔系数h = 1.72±0.15和h = 1.48±0.08，用脂质体胆固醇处理后分别增至h = 2.83±0.55和h = 2.34±0.35。