ACTH_(4-9)类似物对小鼠海马突触体Ca^(2+)水平的调节作用

REGULATION OF ACTH_(4-9)ANALOGUE ON THE Ca^(2+)LEVEL OF MOUSE HIPPOCAMPAL SYNAPTOSOMES

本工作观察了Org2766（ACTH4-9的类似物）对海马突触体内游离Ca2＋水平及对45Ca2＋摄取的影响。采用细胞内钙离子荧光探针Fura－2，通过Spex-阳离子测定系统检测突触体内［Ca2＋］i的动态变化，并用液闪光谱仪测定突触体对45Ca2＋的摄取。结果表明：较低剂量的Orj2766对突触体内［Ca2＋］i的影响不明显，却显著降低突触体对45Ca2＋的摄取；高剂量的Org2766增加突触体内［Ca2＋］I,但对突触体的45Ca2＋摄取无影响。较低剂量的Org2766可拮抗菌香霉素（ANI）升高突触体内［Ca2＋］i和45Ca2＋摄取量的作用，高剂量的Org2766无此效应。此结果提示，Org2766可通过抑制胞外钙内流和增加胞内钙库的释放来调节胞内钙水平。

The effect of ACTH4-9 analogue Org2766 on the [Ca2+], level of mouse hippocampal synaptoSomes was studied. Synaptosomal free calcium concentration ([Ca2+]i) and 45Ca2+ uptake were measured respectively by spex cation measurement system and Beckman LS-9800 liquid scintillation spectrometer. Low dose of Org2766 did not change synaptosomal [Ca2+]i level, but decreased 45Ca2+ uptake. High dose of Org2766increased [ Ca2+ ], without affecting 45Ca2+ uptake. Lom dose of Org2766 inhibited the anisomysin-induced increase of synaptosomal [ Ca2+ ]. while high dose had no effect.These results suggest that the regulation of Org2766 on hippocampal synaptosomal Ca2+level may be achieved by inhibiting the Ca2+ influx and increasing the release of synaptosomal calcium pool.