Khan H R, Price D A, Doble K E, Greenberg M J, Saleuddin A S
Department of Biology, York University, Toronto, Ontario, Canada.
J Comp Neurol. 1998 Mar 30;393(1):25-33.
Serotonergic neurons were studied by specific histological methods, and neurons containing Phe-Met-Arg-Phe-NH2 (FMRFamide)-related heptapeptides were identified with an antiserum specific for these substances in the central nervous system of the freshwater snail Helisoma duryi. Serotonergic neurons and their axons are present in all of the ganglia (paired buccal, cerebral, pedal, pleural, parietal, and single visceral) and major nerves of the central nervous system. Large neurons containing FMRFamide-related peptide immunoreactivity are located in the left parietal and visceral ganglia, whereas a few small neurons are located in the cerebral and pedal ganglia. Both serotonergic and FMRFamide-related peptide-immunoreactive dendrites and varicosities were observed in the kidney. A second antiserum with high affinity for FMRFamide-related heptapeptides was used to measure the levels of the immunoreactive material in various tissues, and such material was found in every tissue analyzed. When snails were exposed to a medium isosmotic to their hemolymph, the levels of immunoreactive FMRFamide-related peptides increased in the hemolymph, central nervous system, mantle, and kidney. Injection of dihydroxytryptamine, which is known to deplete serotonin content in the snail, also reduced the levels of FMRFamide-related-immunoreactive material in the above tissues. Therefore, serotonin may influence the levels of FMRFamide-related peptides in tissues by regulating the rate of their synthesis, axonal transport, or release. Both serotonin and FMRFamide-related peptides could be involved in osmoregulation.
采用特定的组织学方法对5-羟色胺能神经元进行了研究，并在淡水蜗牛杜氏泡螺的中枢神经系统中，用针对这些物质的抗血清鉴定了含有苯丙氨酸-蛋氨酸-精氨酸-苯丙氨酸-酰胺（FMRF酰胺）相关七肽的神经元。5-羟色胺能神经元及其轴突存在于所有神经节（成对的颊神经节、脑神经节、足神经节、胸膜神经节、壁神经节以及单个的内脏神经节）和中枢神经系统的主要神经中。含有FMRF酰胺相关肽免疫反应性的大神经元位于左壁神经节和内脏神经节，而一些小神经元位于脑神经节和足神经节。在肾脏中观察到了5-羟色胺能和FMRF酰胺相关肽免疫反应性的树突和膨体。使用对FMRF酰胺相关七肽具有高亲和力的第二种抗血清来测量各种组织中免疫反应性物质的水平，并且在每个分析的组织中都发现了这种物质。当蜗牛暴露于与其血淋巴等渗的培养基中时，血淋巴、中枢神经系统、外套膜和肾脏中免疫反应性FMRF酰胺相关肽的水平会升高。注射已知会耗尽蜗牛体内5-羟色胺含量的二羟基色胺，也会降低上述组织中FMRF酰胺相关免疫反应性物质的水平。因此，5-羟色胺可能通过调节其合成、轴突运输或释放的速率来影响组织中FMRF酰胺相关肽的水平。5-羟色胺和FMRF酰胺相关肽都可能参与渗透调节。
