汉防己碱与1, 6-二磷酸果糖对兴奋性氨基酸所致突触体内游离钙浓度升高的影响

目的:研究汉防己碱(Tet)与1, 6-二磷酸果糖(FDP)对兴奋性氨基酸(EAA)诱导的突触体内游离钙浓度升高的影响。方法:制备大鼠脑突触体, 以荧光法测定突触体内游离钙浓度;加入谷氨酸(Glu, 100μmol·L^-1), 天冬氨酸(Asp, 100μmol·L^-1), N-甲基-D-天冬氨酸(NMDA, 100μmol·L^-1)及Glu+Asp(50μmol·L^-1+50μmol·L^-1)后, 测定突触体内游离钙浓度的变化;提前给予Tet(10、30、60μmol·L^-1), FDP(15、30、75、150μmol·L^-1), MK-801(10、20μmol·L^-1)及Tet+FDP(10+15, 30+30μmol·L^-1)预孵, 再加入上述浓度的Glu、Asp、NMDA及Glu+Asp, 观察突触体内游离钙浓度的变化。结果:Glu、Asp、NMDA及Glu+Asp均呈剂量依赖性升高突触体内游离钙浓度, 提前给予不同浓度的Tet、FDP、MK-801及Tet+FDP, 均可使突触体内游离钙浓度呈剂量依赖性降低, 且以Tet+FDP的作用最明显。结论:Tet与FPD可显著抑制EAA诱导的突触体内游离钙浓度的升高, 这可能是二者保护缺血脑细胞的作用机制之一。Tet与FDP联合应用可能对缺血脑细胞有更强的保护作用。

Effects of tetrandrine and fructose-1,6-diphosphate on the elevated intrasynaptosomal [Ca2+]i induced by excitatory amino acids

AIM: To study the effects of tetrandrine(Tet) and fructose-1, 6-diphosphate(FDP) on the elevated intrasynaptosomal [Ca²⁺]_i induced by excitatory amino acids(EAA). METHODS: A rapid method for preparing synaptosomes was used, and intrasynaptosomal free calcium([Ca²⁺]_i) was measured by using the fluorescent indicator quin-2. RESULTS: L-glutamate(Glu, 100 μmol/L), aspartate(Asp, 100 μmol·L^-1), N-methy1-D-aspartate(100 μmol/L) and Glu(50 μmol/L) plus Asp(50 μmol/L) all elevated intrasynaptosomal [Ca²⁺]_i in a dose-dependent manner. Pretreatment with Tet(10, 30, 60 μmol/L), FDP(15, 30, 75, 150 μmol/L), MK-801(10, 20 μmol/L) and Tet(15, 30 μmol/L) plus FDP(15, 30 μmol/L) all attenuated the increase in intrasynaptosomal [Ca²⁺]_i induced by EAAs mentioned as above in a dose-dependent manner, and the effect of Tet plus FDP was most significant. CONCLUSION: Both Tet and FDP inhibited a rise in intrasynaptosomal [Ca²⁺]_i induced by EAAs, which may be one of mechanisms that Tet and FDP pretect cerebral tissues against ischemia injury.