神经细胞粘附分子的唾液酸化作用对小鸡记忆的影响

THE POLYSIALIC ACID MODIFICATION OF THE NEURAL CELL ADHESION MOLECULES INVOLVED IN MEMORY RETENTION OF CHICKS

神经细胞粘附分子的多聚唾液酸化不仅影响发育阶段神经元之间的相互作用，而且在学习记忆过程中也起着重要的作用。实验中将特异切割神经细胞粘附分子和多聚唾液酸之间ａ－２，８键的内神经氨酸苷酶ｅｎｄｏｎｅｕｒａｍｉｎｉｄａｓｅＮＥ定位注射到一日龄小鸡脑ＩＭＨＶ内，此酶明显破坏小鸡对一次性被动回避反应的记忆保持。这种破坏作用与酶的剂量有关，小于４μｇ的内神经氨酸苷酶对小鸡的记忆没有明显的影响。对胚胎第２０天的暗孵化小鸡同时注射内神经氨酸苷酶和皮质酮，发现内神经氨酸苷酶能明显阻断皮质酮对这些小鸡记忆的促进作用。这些结果说明，多聚唾液酸可能参与了小鸡的记忆和胚胎期脑的发育过程。

The ploysialic acid (PSA) modification of neural cell adhesion molecules (NCAMs) not onlymodulates cell interaction of neural development but also plays an important role in learning andmemory. The endoneuraminidase NE (endo-N) which specifically removes a-2, 8 linked polysialic acidfrom NCAM was used to assay the functional role of PSA in the chicks memory retention. Thememory retention of day-old chicks was significantly impaired after a localized injection of endo-N intoIMHV. The dose lower than 4μg had no significant effect. The improvement effect of prenatalcorticosterone on memory retention of dark hatched chicks was retarded with endo-N administrationintraplacentally on the embryonic day 20. All these suggested that PSA of NCAM might be involved inmemory retention of chicks and synaptic plasticity during brain development.