Bolliet V, Ali M A
Département de Biologie, Université de Montréal, Québec, Canada.
Brain Behav Evol. 1992;40(5):234-49. doi: 10.1159/000113915.
Serotonin is believed to play an important role in the neuronal development of various invertebrates and mammals, but only one study has yet investigated the development of serotoninergic neurons in the brain of a teleost. In the present study, we investigate the development of serotoninergic neurons in the brain of the brook trout, Salvelinus fontinalis, by immunohistochemistry, from fertilisation to the resorption of the yolk sac and in juveniles for reference. Maintaining trout embryos and larvae in 9L:15D or in complete darkness made no difference in the appearance and distribution of serotonin immunoreactive (5-HTir) neurons. On day 56, the first 5-HTir perikarya, indicative of the primordia of the nuclei raphe medialis/dorsalis, have stained in the presumptive isthmus region. At hatching time (days 95-115), all the 5-HTir nuclei reported in the juvenile are present, except for the population observed in the lobus inferior hypothalami. We observed that the nucleus recessus lateralis stained on day 58, the raphe caudal nucleus on day 60, the nuclei raphe pallidus and obscurus on day 65, the area praetectalis on day 80, and the nucleus recessus posterioris and the anterior group of the nucleus recessus lateralis on day 92. At the complete resorption of the yolk sac (days 175-190), the nucleus reticularis paragigantocellularis, the nuclei raphe pallidus and obscurus and the caudal raphe of the brainstem are very weakly immunoreactive, and in juveniles, only one caudal immunoreactive nucleus is still present. A comparison of our result with those previously reported in the three-spined stickleback, Gasterosteus aculeatus, suggest a similar distribution of 5-HTir neurons in the brain of both species but also reveal species differences in the sequence of appearance of 5HT immunoreactivity in the different neuronal populations.
血清素被认为在各种无脊椎动物和哺乳动物的神经元发育中起重要作用，但仅有一项研究调查了硬骨鱼脑中血清素能神经元的发育情况。在本研究中，我们通过免疫组织化学方法，研究了溪红点鲑（Salvelinus fontinalis）从受精到卵黄囊吸收以及幼鱼阶段脑中血清素能神经元的发育情况以供参考。将鳟鱼胚胎和幼体置于9小时光照：15小时黑暗环境或完全黑暗环境中，血清素免疫反应性（5-HTir）神经元的外观和分布没有差异。在第56天，第一批5-HTir核周体（指示中缝内侧/背侧核的原基）在假定的峡部区域被染色。在孵化时（第95 - 115天），幼鱼中报道的所有5-HTir核都已出现，但下丘脑下部叶中观察到的群体除外。我们观察到，外侧隐窝核在第58天被染色，中缝尾核在第60天被染色，中缝苍白核和中缝 obscurus核在第65天被染色，视前区在第80天被染色，后隐窝核和外侧隐窝核前组在第92天被染色。在卵黄囊完全吸收时（第175 - 190天），网状旁巨细胞核、中缝苍白核和中缝obscurus核以及脑干的尾侧中缝免疫反应性非常弱，在幼鱼中，仅仍存在一个尾侧免疫反应性核。将我们的结果与先前在三刺鱼（Gasterosteus aculeatus）中报道的结果进行比较，表明两种物种脑中5-HTir神经元的分布相似，但也揭示了不同神经元群体中5-HT免疫反应性出现顺序的物种差异。
