Garrett J R, Winston D C, Proctor G B, Schulte B A
Department of Oral Pathology, King's College School of Medicine and Dentistry, Rayne Institute, London, U.K.
Arch Oral Biol. 1992 Sep;37(9):711-6. doi: 10.1016/0003-9969(92)90077-l.
Sections from normal resting submandibular glands were incubated in a p-nitrophenylphosphate substrate mixture to demonstrate Na,K-ATPase activity by light and electron microscopy. Dense deposits of reaction product occurred within the basal and lateral infoldings of striated duct cells. A similar, less heavy deposition occurred in demilune cells. Only scattered, infrequent pockets of staining occurred in association with the basal plasma membrane of central acinar cells, supporting the belief that these cells do not contribute greatly to the secretion of fluid. No reaction was detected on luminal membranes. Glands tested after sympathetic or parasympathetic nerve stimulation showed no obvious differences from resting glands. These results contrast with the previously reported paucity of immunostaining in resting demilunes with an antibody to Na,K-ATPase and the large increase in the immunostaining by these cells after parasympathetic stimulation. It is inferred that there must be an inaccessibility to immunobinding sites of Na,K-ATPase in resting glands, and that the increase in binding which occurs after parasympathetic stimulation represents a conformational change that did not affect its enzyme catalytic reaction with this substrate.
将正常静息状态下的下颌下腺切片置于对硝基苯磷酸底物混合物中孵育，通过光学显微镜和电子显微镜观察钠钾 - ATP酶活性。反应产物的致密沉积物出现在纹状管细胞的基底和侧褶内。半月细胞中也有类似但程度较轻的沉积物。仅在中央腺泡细胞的基底质膜处出现散在、罕见的染色点，这支持了这些细胞对液体分泌贡献不大的观点。在管腔膜上未检测到反应。交感神经或副交感神经刺激后测试的腺体与静息腺体无明显差异。这些结果与先前报道的用抗钠钾 - ATP酶抗体检测静息半月细胞中免疫染色缺乏以及副交感神经刺激后这些细胞免疫染色大幅增加形成对比。据推测，静息腺体中钠钾 - ATP酶的免疫结合位点一定难以接近，而副交感神经刺激后结合增加代表了一种构象变化，这种变化并未影响其与该底物的酶催化反应。
