Yamamoto T, Geiger J D, Daddona P E, Nagy J I
Department of Pharmacology, University of Manitoba Faculty of Medicine, Winnipeg.
Brain Res Bull. 1987 Oct;19(4):473-84. doi: 10.1016/0361-9230(87)90152-3.
Immunohistochemical and subcellular fractionation techniques were employed to compare the cellular and subcellular localization of adenosine deaminase (ADA) in various brain regions of several mammalian species. A relatively restricted distribution of ADA-immunoreactive neurons in rat brain was previously reported. Mouse brain exhibited a pattern similar in many respects to rat and, in addition, contained intensely immunostained neurons in lateral habenula and hippocampus. Glial immunostaining was absent or very light in rat but evident in mouse. Prominent immunoreactive fibers and neurons were observed in hamster spinal cord and anterior hypothalamus, respectively. ADA-immunostaining in guinea-pig was localized to presumptive fibers in the superficial layers of spinal cord dorsal horn and to glial cells throughout the brain. Demonstration of specific immunostaining in rabbit was not possible. ADA activity was far more heterogeneously distributed in rat and most brain areas in guinea-pig and rabbit contained up to 5-fold and 10-fold higher levels of activity, respectively, compared with rat. Crude synaptosomal (P2) fractions of rat cortex contained a greater proportion of ADA activity than those of rabbit cortex. Within rat, relatively high activity was found in P2 fractions of whole hypothalamus, cerebellum, and hippocampus. ADA activity was greater in P2 fractions of rat anterior compared with whole hypothalamus and the greatest proportion of the enzyme in this fraction was localized to purified synaptosomes. The large variations in the activity and cellular location of ADA in the animals examined suggest species differences in mechanisms governing adenosine metabolism in brain and possible differences in the relationships between cellular metabolism, ADA and the neuroregulatory role of adenosine in the CNS.
采用免疫组织化学和亚细胞分级分离技术，比较几种哺乳动物不同脑区中腺苷脱氨酶（ADA）的细胞和亚细胞定位。先前报道了大鼠脑中ADA免疫反应性神经元分布相对局限。小鼠脑在许多方面呈现出与大鼠相似的模式，此外，在外侧缰核和海马中含有免疫染色强烈的神经元。大鼠中胶质细胞免疫染色缺失或非常淡，但在小鼠中明显。分别在仓鼠脊髓和下丘脑前部观察到显著的免疫反应性纤维和神经元。豚鼠中的ADA免疫染色定位于脊髓背角浅层的推定纤维和全脑的胶质细胞。无法在兔中证实特异性免疫染色。与大鼠相比，ADA活性在大鼠中分布更为不均一，豚鼠和兔的大多数脑区活性分别高达大鼠的5倍和10倍。大鼠皮质的粗突触体（P2）级分中ADA活性的比例高于兔皮质。在大鼠中，全下丘脑、小脑和海马的P2级分中发现相对较高的活性。与全下丘脑相比，大鼠前部P2级分中的ADA活性更高，该级分中该酶的最大比例定位于纯化的突触体。所检查动物中ADA活性和细胞定位的巨大差异表明，在调节脑内腺苷代谢的机制上存在物种差异，以及细胞代谢、ADA与腺苷在中枢神经系统中的神经调节作用之间的关系可能存在差异。
