Serfözö Z, Elekes K, Varga V
Department of Animal Physiology, Lajos Kossuth University, Debrecen, Hungary.
Cell Tissue Res. 1998 Jun;292(3):579-86. doi: 10.1007/s004410051087.
Nicotinamide-adenine-dinucleotide-phosphate-diaphorase (NADPH-d) histochemistry has been applied in the present study to determine the distribution of putative nitric oxide (nitric oxide synthase)-producing cells during embryonic and early postembryonic development in the pond snail, Lymnaea stagnalis L., with special reference to the nervous system. The first NADPH-d-positive structures appear as early as 18% of development (E18, trochophore stage) and correspond to the pair of protonephridia. These structures later show disintegration, although after metamorphosis (E26=75%) staining of their individually spreading cells can be observed until hatching. Peripheral sensory neurons in the foot, mantle edge and lips, and their afferents projecting to the central nervous system reveal NADPH-d activity in the postmetamorphosis period (E25-E27=E60%-E80%) of embryogenesis. After hatching (P1-P3), a number of stained sensory cells appear in the pharynx and esophagus. Some NADPH-d positive neuronal perikarya occur in the pedal and pleural ganglia, and a few weakly stained cells in the cerebral and buccal ganglia of juvenile snails. At the same time, a continuous bundle of reactive fibers is formed in the neuropil both through and through around the circumesophageal ganglion ring. The localization of NADPH-d activity in the developing nervous system of Lymnaea suggests that nitric oxide participates mainly in sensory processes. However, its role in specific intraganglionic integrative events cannot be excluded following embryonic metamorphosis.
本研究应用烟酰胺腺嘌呤二核苷酸磷酸黄递酶（NADPH-d）组织化学方法，以确定椎实螺胚胎期和胚后早期发育过程中假定的一氧化氮（一氧化氮合酶）产生细胞的分布情况，特别关注神经系统。最早在发育的18%（E18，担轮幼虫期）就出现了NADPH-d阳性结构，对应于一对原肾管。这些结构随后出现解体，不过在变态后（E26 = 75%），在孵化前仍可观察到其单个分散细胞的染色。足部、外套膜边缘和唇部的外周感觉神经元及其投射到中枢神经系统的传入神经，在胚胎发育的变态后期（E25 - E27 = E60% - E80%）显示出NADPH-d活性。孵化后（P1 - P3），咽部和食管中出现了一些染色的感觉细胞。一些NADPH-d阳性神经元胞体出现在足神经节和胸膜神经节中，幼螺的脑和口神经节中有一些弱染色细胞。与此同时，在围绕食管神经节环的神经纤维网中形成了一束连续的反应性纤维。椎实螺发育中的神经系统中NADPH-d活性的定位表明，一氧化氮主要参与感觉过程。然而，在胚胎变态后，不能排除其在神经节内特定整合事件中的作用。
