神经肽DGAVP和Org2766对神经细胞内游离Ca2+的影响

运用Ca²⁺指示剂Fura-2作为细胞内钙离子的荧光探针,利用AR—CM—MIC阳离子测定系统,检测了分离的神经细胞内游离钙及其变化,并观测了DGAVP和Org2766对蛋白质合成抑制剂茴香霉素(ANI)引起细胞内钙离子浓度(Ca²⁺]_i)变化的影响。结果表明茴香霉素可使Ca²⁺]_i显著升高,且有量效关系;DGAVP本身并不引起Ca²⁺]_i发生显著变化,但适当剂量的DGAVP可显著对抗一定剂量范围内ANI升高Ca²⁺]_i的作用,提示DGAVP对抗ANI的蛋白质合成抑制效应可能是通过拮抗ANI升高Ca²⁺]_i这一途径实现的,另一神经肽Org2766则可能不是通过这一机制发生作用。从细胞内Ca²⁺的角度看,这两种肽的作用机理显然是不同的。

EFFECT OF DGAVP AND Org2766 ON INTRACELLULAR FREE Ca2+ CONCENTRATION IN DISSOCIATED BRAIN CELLS

Intracellular free calcium concentration (Ca²⁺]_i) was measured with Fura-2 in freshly dissociated brain cells isolated from newborn (1～2 day) mouse pups using AR—CM—MIC cation measurement system, and the effects of DGAVP and Org2766 on the changes in Ca²⁺]_i induced by the protein synthesis inhibitor anisomycin (ANI) were studied. The results indicate that anisomycin caused dose-dependent increases in Ca²⁺]_i; and DGAVP itself showed no significant effect on Ca²⁺]_i, but an appropriate dose of DGAVP antagonized the increases induced by the selective dose-range of ANI, suggesting that the antagonism of ANI-induced inhibition of protein synthesis by DGAVP was likely achieved by preventing ANI from increasing Ca²⁺]_i, but this mechanism did not apply to the other neuropeptide Org2766. Therefore, we suppose that the mechanism of the two neuropeptides are different in terms of their effect on intracellular free calcium concentration.