目的　探讨中枢神经髓鞘膜蛋白抑制神经突起生长与神经元胞内cAMP水平的关系。　方法　应用体外培养方法观察经密度梯度离心法提取的中枢神经髓鞘膜蛋白对小脑颗粒细胞突起生长的影响 ,用放射免疫方法检测神经元接触髓鞘膜蛋白后胞内cAMP水平的变化。　结果　 1 中枢神经髓鞘膜蛋白抑制培养小脑颗粒细胞突起的生长 ;2 神经元接触髓鞘膜蛋白后的最初 5min ,胞内cAMP水平即开始下降 ,12h降至最低点。　结论中枢神经髓鞘膜蛋白抑制神经突起生长的作用可能与抑制因子通过信号转导使神经元胞内cAMP水平降低有关 Objective To investigate the relationship between inhibition of neurite outgrowth by central myelin membrane protein and intracellular cAMP level in neurons. Methods In vitro culture was used to observe the effect of central myelin membrane protein extracted from density gradient centrifugation on the growth of cerebellar granule cells. The intracellular cAMP level was detected by radioimmunoassay after contact of neurons with myelin membrane protein. Results 1 Central myelin membrane protein inhibited the growth of cultured cerebellar granulosa cells; 2 neurons contact myelin membrane protein in the first 5min, intracellular cAMP levels began to decline, 12h to the lowest point. Conclusion The inhibitory effect of central myelin membrane protein on neurite outgrowth may be related to the decrease of intracellular cAMP level by inhibition of signal transduction