Davis W L, Jones R G, Hagler H K, Farmer G R, Goodman D B
Anat Rec. 1987 Jul;218(3):229-36. doi: 10.1002/ar.1092180302.
The ultrahistochemical analysis of apical granules in the epithelial cells, i.e., granular cells, of the amphibian urinary bladder using the N,N-naphthaloylhydroxylamine procedure identified the presence of calcium in these structures. Subsequent analytical microscopy employing fresh-frozen ultrathin cryosections for X-ray microanalysis of the granules further confirmed the above histochemical findings. In addition to calcium, elemental analysis indicated the presence of magnesium, phosphorus, sulfur, silicon, potassium, and chlorine either within or in close proximity to the granules. The possibility that these granules function as subcellular compartments for the uptake and storage of calcium ions, in a way similar to mitochondria, and thus function in intracellular calcium homeostasis, is discussed. Additionally, a role for this cation in the secretion of granular glycoproteins, i.e., stimulus-secretion coupling, is hypothesized.
采用N，N-萘甲酰羟胺法对两栖动物膀胱上皮细胞（即颗粒细胞）顶端颗粒进行超组织化学分析，确定这些结构中存在钙。随后，利用新鲜冷冻超薄冰冻切片对颗粒进行X射线微量分析的分析显微镜检查进一步证实了上述组织化学结果。除钙外，元素分析表明颗粒内部或其附近存在镁、磷、硫、硅、钾和氯。本文讨论了这些颗粒可能作为亚细胞区室，以类似于线粒体的方式摄取和储存钙离子，从而在细胞内钙稳态中发挥作用的可能性。此外，还推测了这种阳离子在颗粒糖蛋白分泌中的作用，即刺激-分泌偶联。
