突触中磷蛋白的生后发育变化

为了研究在突触功能中起重要作用的磷蛋白状况，利用高分辩率的放射自显影、梯度电泳和双向电泳，以及抗ＣａＮ多克隆抗体封闭ＣａＮ磷酸酶活力等技术，并运用计算机图象处理系统，对大鼠大脑皮层突触体中磷蛋白生后发育变化进行定量分析．结果表明，大鼠出生后（ＰＮＤ）３ｄ、７ｄ、２１ｄ、和成年磷蛋白表达有很大不同，在出生后早期对应突触主要形成时期，磷蛋白呈高表达；从ＰＮＤ２１ｄ开始至成年，底物蛋白磷酸化状态逐渐降低，同时研究了突触主要形成时期有显著变化的钙调神经磷酸酶，它的内源底物及其在其生后发育所发生的变化．

Postnatal Developmental Expression of Phosphoproteins in Synaptosome

The regulation of the phosphorylation state of specific substrate proteins by protein kinases and phosphatases plays a pivotal role in neuronal functions.In the developing mammalian brain,these phosphoproteins are important for the formation of synapses during the postnatal period. Therefore,the elucidation of the changes of these substrates involving the different phasing of synapse formation is an essential step toward understanding the nervous system function.To detect these phosphoproteins,postnatal developmental expression of phosphoproteins were quantitatively assayed in rat cerebral cortex synaptosome.Phosphoproteins expression showed developmental changes in rat cerebral cortex synaptosome on postnatal days(PND)3,7,21 and adult. 32 P labelled phosphoproteins appeared in high level during the periods corrdsponding to major synapse formation.Phosphorylation of substrate proteins began to decrease until PND 21.It has been suggested that the Ca 2 /calmodulin dependent protein phosphatase 2B,or calcineurin(CaN)are highly expressed during the major period of synapse formation.CaN endogenous substrates were detected in rat cerebral cortex synaptosome on PND3,PND7,PND21 and adult using anti CaN polycolonal antibody,gradient SDS PAGE and autoradiagraphy.Further studies were undertaken to examine whether the expression levels of CaN substrate proteins would change following the developmental pattern.