Electron microscopy revealed that glial cells in the posterior sub-esophageal mass of the brain in Sepia officinalis had a well-developed rough endoplasmic reticulum formed by long coverslips with rectilinear or curvilinear arrangements. The coverslips appeared dilated and have a large amount of adhered polysomes. Vesicular lamellae coexisted with the elongated lamellae of RER and dictyosomes of Golgi apparatus. Endocytosis was evidenced through the pale vesicles which were appeared next to the apical border of microvilli in some glial cells. Sub-cellular features of endocytosis, predominantly the fluid phase, were observed in the apical glial cell cytoplasm. Glial cells were related to phagocytosis of apoptotic neurons, endocytosis, pinocytosis and adsorption. These functions were proposed based on their ultrastructure characteristics and a significant number of vesicles with different shapes (oval to polygonal), sizes 0.052–0.67 µm and contents. Glycogen, MPS and lipid were detected in the glial cells. Alkaline phosphatase was not observed, while an activity of acid phosphatase was bound to lysosomes. ATPases were present in the glial cells along the lateral and basal plasma lemma as well as on the membranes of cell organelles. Unspecific esterase was clearly recognizable by electron microscopy. The monoamine and cytochrome oxidase activities were demonstrated, while the succinate dehydrogenase showed a weak enzyme activity.

电镜显示，乌贼脑后食管下团块中的胶质细胞具有发育良好的粗面内质网，由直线或曲线排列的长盖玻片形成。盖玻片出现扩张并具有大量粘附的多核糖体。囊泡片层与 RER 的细长片层和高尔基体的盘状体共存。通过一些神经胶质细胞中微绒毛顶端边缘附近出现的苍白囊泡证明了内吞作用。在顶端胶质细胞的细胞质中观察到内吞作用的亚细胞特征，主要是液相。胶质细胞与凋亡神经元的吞噬作用、内吞作用、胞饮作用和吸附作用有关。这些功能是根据其超微结构特征和大量不同形状（椭圆形到多边形）、尺寸 0.052–0.67 µm 和含量的囊泡提出的。在神经胶质细胞中检测到糖原、MPS 和脂质。未观察到碱性磷酸酶，而酸性磷酸酶的活性与溶酶体结合。 ATP酶存在于神经胶质细胞中，沿着外侧和基底质外膜以及细胞器的膜上。通过电子显微镜可以清楚地识别出非特异性酯酶。证明了单胺和细胞色素氧化酶活性，而琥珀酸脱氢酶表现出弱酶活性。