Nakamura H
Department of Anatomy, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
J Comp Neurol. 1997 Sep 8;385(4):616-26.
Nitric oxide synthase (NOS), argininosuccinate synthetase (ASS), and argininosuccinate lyase (ASL) compose a cyclic pathway to form nitric oxide (NO). These enzymes, however, are localized differentially in most regions of the brain. To find out whether NOS, ASS, and ASL are colocalized in neurons of the spinal cord, we examined the distribution of these enzymes by using a double-labeling procedure combining fluorescent immunohistochemistry with an assay for reduced nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d). Results indicate that neurons in the dorsal horn, the intermediolateral nucleus, and the central canal region were NADPH-d active (+) and NOS-, ASS-, and ASL-like immunoreactive (-LI). In laminae II and III of the dorsal horn, some NADPH-d (+) neurons were ASL-LI (8-30%) but only a few were ASS-LI (0.5-7%). In the nucleus intermediolateralis, a large portion of NADPH-d (+) neurons were ASL-LI (30-60%), whereas only a small portion of NADPH-d (+) neurons were ASS-LI (10-20%). In the central canal region, some NADPH-d (+) neurons were ASL-LI (15-40%), and a few NADPH-d (+) neurons were ASS-LI (3-16%). Thus, the results suggest that, in the nucleus intermediolateralis and the central canal region, NOS, ASS, and ASL are colocalized and form a cyclic pathway to produce NO, whereas, in the dorsal horn, these enzymes are more characteristically localized in different neurons, which may transport the substrates intercellularly.
一氧化氮合酶（NOS）、精氨琥珀酸合成酶（ASS）和精氨琥珀酸裂解酶（ASL）构成了一条生成一氧化氮（NO）的循环途径。然而，这些酶在大脑的大多数区域中分布不同。为了弄清楚NOS、ASS和ASL是否在脊髓神经元中共定位，我们通过将荧光免疫组织化学与还原型烟酰胺腺嘌呤二核苷酸磷酸黄递酶（NADPH-d）检测相结合的双标记程序，研究了这些酶的分布情况。结果表明，背角、中间外侧核和中央管区域的神经元呈NADPH-d活性（+），且无NOS、ASS和ASL样免疫反应性（-LI）。在背角的Ⅱ层和Ⅲ层中，一些NADPH-d（+）神经元呈ASL-LI（8%-30%），但只有少数呈ASS-LI（0.5%-7%）。在中间外侧核中，大部分NADPH-d（+）神经元呈ASL-LI（30%-60%），而只有一小部分NADPH-d（+）神经元呈ASS-LI（10%-20%）。在中央管区域，一些NADPH-d（+）神经元呈ASL-LI（15%-40%），少数NADPH-d（+）神经元呈ASS-LI（3%-16%）。因此，结果表明，在中间外侧核和中央管区域，NOS、ASS和ASL共定位并形成一条产生NO的循环途径，而在背角中，这些酶更典型地定位于不同的神经元中，这些神经元可能在细胞间转运底物。
