Kántor Orsolya, Varga Alexandra, Kovács-Öller Tamás, Énzsöly Anna, Balogh Lajos, Baksa Gábor, Szepessy Zsuzsanna, Fonta Caroline, Roe Anna Wang, Nitschke Roland, Szél Ágoston, Négyessy László, Völgyi Béla, Lukáts Ákos
Department of Anatomy, Histology and Embryology, Semmelweis University, Tűzoltó u. 58, Budapest, 1094, Hungary,
Cell Tissue Res. 2014 Oct;358(1):85-98. doi: 10.1007/s00441-014-1944-3. Epub 2014 Jul 3.
Evidence is emerging with regard to the role of tissue non-specific alkaline phosphatase (TNAP) in neural functions. As an ectophosphatase, this enzyme might influence neural activity and synaptic transmission in diverse ways. The localization of the enzyme in known neural circuits, such as the retina, might significantly advance an understanding of its role in normal and pathological functioning. However, the presence of TNAP in the retina is scarcely investigated. Our multispecies comparative study (zebrafish, cichlid, frog, chicken, mouse, rat, golden hamster, guinea pig, rabbit, sheep, cat, dog, ferret, squirrel monkey, human) using enzyme histochemistry and Western blots has shown the presence of TNAP activity in the retina of several mammalian species, including humans. Although the TNAP activity pattern varies across species, we have observed the following trends: (1) in all investigated species (except golden hamster), retinal vessels display TNAP activity; (2) TNAP activity consistently occurs in the photoreceptor layer; (3) in majority of the investigated species, marked TNAP activity is present in the outer and inner plexiform layers. In zebrafish, frog, chicken, guinea pig, and rat, TNAP histochemistry has revealed several sublayers of the inner plexiform layer. Frog, golden hamster, guinea pig, mouse, and human retinas possess a subpopulation of amacrine cells positively staining for TNAP activity. The expression of TNAP in critical sites of retinal signal transmission across a wide range of species suggests its fundamental, evolutionally conserved role in vision.
关于组织非特异性碱性磷酸酶（TNAP）在神经功能中的作用，相关证据正在不断涌现。作为一种胞外磷酸酶，这种酶可能以多种方式影响神经活动和突触传递。该酶在已知神经回路（如视网膜）中的定位可能会极大地推动对其在正常和病理功能中作用的理解。然而，视网膜中TNAP的存在情况几乎未被研究。我们利用酶组织化学和蛋白质免疫印迹法进行的多物种比较研究（斑马鱼、丽鱼、青蛙、鸡、小鼠、大鼠、金黄仓鼠、豚鼠、兔子、绵羊、猫、狗、雪貂、松鼠猴、人类）表明，包括人类在内的几种哺乳动物的视网膜中存在TNAP活性。尽管TNAP的活性模式因物种而异，但我们观察到了以下趋势：（1）在所有被研究的物种中（除金黄仓鼠外），视网膜血管显示出TNAP活性；（2）TNAP活性始终存在于光感受器层；（3）在大多数被研究的物种中，内外网状层中存在明显的TNAP活性。在斑马鱼、青蛙、鸡、豚鼠和大鼠中，TNAP组织化学揭示了内网状层的几个亚层。青蛙、金黄仓鼠、豚鼠、小鼠和人类的视网膜拥有一群对TNAP活性呈阳性染色的无长突细胞。TNAP在广泛物种的视网膜信号传递关键位点的表达表明其在视觉中具有基本的、进化上保守的作用。
