琥珀酰缩胆囊素七肽对小鼠海马突触体摄取^(45)Ca的影响(英文)

Effect of succinyl cholecystokinin heptapeptide on synaptosomal 45Ca uptake of mouse hippocampus

目的;探讨琥珀酰缩胆囊素七肽(SCH)对小鼠海马突触体摄取^(45)Ca的影响,并与辛卡利特作.了比较.方法:蛋白质浓度的测定用染料法.^(45)Ca的摄取测定采用^(45)CaCl_2加入突触体悬液中孵育后用玻璃微纤维过滤器过滤,用液闪光谱仪计数.结果:SCH是辛卡利特异构物.实验表明在0.125—2 μmol·L^(-1)的剂量范围内SCH呈剂量依赖性地抑制小鼠海马突触体摄取^(45)Ca.其抑制的程度与辛卡利特近似.SCH与辛卡利特的这种抑制效应能被丙谷胺、β-内啡肽所拮抗.结论:辛卡利特N端天冬氨酸残基的改变对海马突触体摄取^(45)Ca无明显影响.

AIM:To study the effect of a new peptide, succinyl cholecystokinin heptapeptide (SCH) , on the uptake of 45Ca by synaptosomes from mouse hippocampus, and compare it with that of sincalide. METHODS: Protein concentration was determined by the dye method. 45Ca uptake was determined by adding 45CaCl2 into synaptosome suspending solution. Samples were incubated and terminated by filtration through glass microfiber filters and finally counted in a Beckman LS 9800 liquid scintillation spectrometer. RESULTS:SCH 0. 125 - 2umol.L-1 dose-dependently depressed synaptosomal 45Ca uptake, and the depressive extent was similar to that of sincalide. The suppressive effect induced by either SCH or sincalide on synaptosomal 45Ca uptake was antagonized by proglumide, which itself did not affect 45Ca uptake of synaptosomes. The inhibition of synaptosomal 45Ca uptake induced by SCH or sincalide was blocked by B-endorphin. CONCLUSION, The replacement of the N-terminal aspartic acid residue of sincalide does not influence its effect on 45Ca uptake of hippocampal synaptosomes.