Kharazia V N, Schmidt H H, Weinberg R J
Department of Cell Biology & Anatomy, University of North Carolina, Chapel Hill 27599.
Neuroscience. 1994 Oct;62(4):983-7. doi: 10.1016/0306-4522(94)90337-9.
The novel gaseous neuromediator nitric oxide is thought to play an important role in development and plasticity. Despite this, gene-knockout mice lacking neuronal (Type I) nitric oxide synthase exhibit relatively normal brain development and behavior. The nervous system of these mice (especially the forebrain) retains some calcium-dependent nitric oxide synthesis, presumably reflecting other isozymes. Type I nitric oxide synthase has NADPH-dependent diaphorase activity. However, this stain also recognizes other isozymes, and it remains controversial whether all diaphorase-positive neurons contain Type I nitric oxide synthase. To assess whether neurons containing another isoform of nitric oxide synthase may be present in the forebrain of normal rodents, we studied co-localization of diaphorase staining with immunocytochemistry for Type I nitric oxide synthase. Co-localization was complete in the striatum, but some neurons deep in cortex were diaphorase-positive and immunonegative, and therefore may contain a splice variant or novel isozyme of nitric oxide synthase.
新型气态神经介质一氧化氮被认为在发育和可塑性过程中发挥重要作用。尽管如此，缺乏神经元型（I型）一氧化氮合酶的基因敲除小鼠表现出相对正常的脑发育和行为。这些小鼠的神经系统（尤其是前脑）保留了一些钙依赖性一氧化氮合成，推测这反映了其他同工酶。I型一氧化氮合酶具有NADPH依赖性黄递酶活性。然而，这种染色也能识别其他同工酶，并且所有黄递酶阳性神经元是否都含有I型一氧化氮合酶仍存在争议。为了评估正常啮齿动物前脑中是否可能存在含有另一种一氧化氮合酶同工型的神经元，我们研究了黄递酶染色与I型一氧化氮合酶免疫细胞化学的共定位。在纹状体中共定位是完全的，但皮质深处的一些神经元是黄递酶阳性且免疫阴性，因此可能含有一氧化氮合酶的剪接变体或新型同工酶。
