Croll R P, Voronezhskaya E E, Hiripi L, Elekes K
Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
J Comp Neurol. 1999 Feb 15;404(3):297-309. doi: 10.1002/(sici)1096-9861(19990215)404:3<297::aid-cne2>3.0.co;2-i.
Catecholamines have long been thought to play important roles in different mollusc neural functions. The present study used glyoxylate- and aldehyde-induced histofluorescence to identify central and peripheral catecholaminergic neurons in the snail Lymnaea stagnalis. The majority of these cells were also found to react to antibodies raised against tyrosine hydroxylase. A minority of the catecholaminergic neurons, however, exhibited no such immunoreactivity. The number of central catecholaminergic neurons nearly doubled (from about 45 to about 80 cells) during the first 2-3 days of postembryonic development. Thereafter, catecholaminergic neurons again doubled in number and generally grew by about 100-200% in soma diameter as the snails grew by 1,000% in overall linear measurements. In contrast to the relatively meager addition of central catecholaminergic neurons, several thousand catecholaminergic somata were added to different peripheral tissues during postembryonic development. These small, centrally projecting neurons were particularly concentrated in the lips, esophagus, anterior margin of the foot, and different regions of the male and female reproductive tracts. Chromatographic analyses indicated that dopamine was the major catecholamine present in the central ganglia, foot, and esophagus, although detectable levels of norepinephrine (approximately 20% of dopamine levels) were also found in the ganglia. The total content but not the concentration of dopamine increased within the tissue samples during postembryonic development. The companion study (Voronezhskaya et al. [1999] J. Comp. Neurol. 404:285-296) and the present study furnish a complete description of central and peripheral catecholaminergic neurons from their first appearance in early embryonic development to adulthood.
长期以来，人们一直认为儿茶酚胺在不同的软体动物神经功能中发挥着重要作用。本研究利用乙醛酸和醛诱导的组织荧光来识别椎实螺中枢和外周的儿茶酚胺能神经元。还发现这些细胞中的大多数对针对酪氨酸羟化酶产生的抗体有反应。然而，少数儿茶酚胺能神经元没有这种免疫反应性。在胚胎后发育的头2 - 3天，中枢儿茶酚胺能神经元的数量几乎翻倍（从约45个细胞增加到约80个细胞）。此后，随着蜗牛整体线性尺寸增长1000%，儿茶酚胺能神经元数量再次翻倍，其胞体直径通常增长约100 - 200%。与中枢儿茶酚胺能神经元相对较少的增加形成对比的是，在胚胎后发育过程中，数千个儿茶酚胺能细胞体被添加到不同的外周组织中。这些小的、向中枢投射的神经元特别集中在唇部、食道、足部前缘以及雄性和雌性生殖道的不同区域。色谱分析表明，多巴胺是中枢神经节、足部和食道中存在的主要儿茶酚胺，尽管在神经节中也发现了可检测水平的去甲肾上腺素（约为多巴胺水平的20%）。在胚胎后发育过程中，组织样本中多巴胺的总量增加，但浓度未增加。配套研究（沃罗涅日斯卡娅等人[1999年]《比较神经学杂志》404:285 - 296）和本研究完整描述了中枢和外周儿茶酚胺能神经元从胚胎早期发育首次出现到成年期的情况。
