González A, Tuinhof R, Smeets W J
Departamento de Biología Celular, Facultad de Biología, Universidad Complutense, Madrid, Spain.
Anat Embryol (Berl). 1993 Feb;187(2):193-201. doi: 10.1007/BF00171750.
The distribution of dopamine (DA) and the biosynthetic enzyme tyrosine hydroxylase (TH) has been studied immunohistochemically in the brain of the adult South African clawed frog, Xenopus laevis. The goals of the present study are, firstly, to provide detailed information on the DA system of the brain of a species which is commonly used in laboratories as an experimental model and, secondly, to enhance our insight into primitive and derived characters of this catecholaminergic system in amphibians. Dopamine-immunoreactive cell bodies are present in the olfactory bulb, the preoptic area, the suprachiasmatic nucleus, the nucleus of the periventricular organ and its accompanying cells, the nucleus of the posterior tubercle, the posterior thalamic nucleus, the midbrain tegmentum, around the solitary tract, in the ependymal layer along the midline of the caudal rhombencephalon, and along the central canal of the spinal cord. In contrast to the DA antiserum, the TH antiserum fails to stain the liquor-contacting cells in the periventricular organ. On the contrary, the latter antiserum reveals additional immunoreactive cell bodies in the olfactory bulb, the isthmic region and the caudal brainstem. Both antisera yield an almost identical distribution of fibers. Distinct fiber plexuses are observed in the olfactory bulb, the basal forebrain, the hypothalamus and the intermediate lobe of the hypophysis. Features that Xenopus shares with other anurans are the larger number of DAi cells, which are generally smaller in size than those observed in urodeles, and the lack of DAi fibers in pallial structures. On the other hand, the paired midbrain DA cell group and the innervation of the tectum of Xenopus resemble those found in the newt rather than those in frogs. Despite the existence of these species differences, the brain of Xenopus offers an excellent model for studying general aspects of neurotransmitter interactions and the development of catecholamine systems in this class of vertebrates.
运用免疫组织化学方法，对成年南非爪蟾（非洲爪蟾）大脑中的多巴胺（DA）分布及生物合成酶酪氨酸羟化酶（TH）进行了研究。本研究的目的，其一，是为一种常用于实验室作为实验模型的物种的大脑DA系统提供详细信息；其二，是增进我们对两栖类动物这一儿茶酚胺能系统的原始特征和衍生特征的理解。多巴胺免疫反应性细胞体存在于嗅球、视前区、视交叉上核、脑室周器官及其伴随细胞的核、后结节核、丘脑后核、中脑被盖、孤束周围、尾侧菱脑中线处的室管膜层以及脊髓中央管沿线。与DA抗血清不同，TH抗血清未能使脑室周器官中的接触脑脊液细胞染色。相反，后一种抗血清在嗅球、峡部区域和尾侧脑干中发现了额外的免疫反应性细胞体。两种抗血清产生的纤维分布几乎相同。在嗅球、基底前脑、下丘脑和垂体中间叶观察到明显的纤维丛。非洲爪蟾与其他无尾两栖类动物共有的特征是，多巴胺免疫反应性（DAi）细胞数量较多，其大小通常比有尾两栖类动物中的DAi细胞小，并且在脑皮质结构中缺乏DAi纤维。另一方面，非洲爪蟾成对的中脑DA细胞群和顶盖的神经支配类似于蝾螈，而非蛙类。尽管存在这些物种差异，但非洲爪蟾的大脑为研究这类脊椎动物神经递质相互作用的一般方面以及儿茶酚胺系统的发育提供了一个极好的模型。
