大鼠黑质多巴胺能神经元的形态学发育

目的探讨大鼠黑质多巴胺(DA)能神经元的形态学发育和分布特征。方法行大鼠出生前后不同时期的脑黑质区段连续冠状石蜡切片，以酪氨酸羟化酶(TH)免疫组织化学染色方法显示DA能神经元，焦油紫染色确定黑质区域，进行光镜观察以及细胞形态学指标的测量。结果胚胎(embryonicclay，E)第13天龄(E13)时，开始于中脑腹侧出现TH阳性(TH^ )细胞。至E16时，中脑腹侧这些细胞的数量和密度达到最大值，此后又逐渐下降，且于出生后早期这些TH^ 细胞的减少最为显著。至生后第14天龄(P14)时，中脑腹侧黑质区域TH^ 细胞的分布和密度不再明显改变，与成年期状态接近。胚胎期，TH^ 细胞多为圆形或椭圆形，随着胚胎发育，其突起逐渐伸长，分支也逐渐增多。出生后，TH^ 细胞逐渐表现为成熟神经元的形态特征。结论大鼠脑黑质DA能神经元的发育发生在个体出生前后，呈现先大量形成后又逐渐减少的过程，与此同时，其形态趋向成熟。至P14时，DA能神经元的分布和形态学发育基本成熟。

The morphological development of the dopaminergic neurons in rat substantia nigra

Objective To explore the morphological changes and distributing features of dopaminergic neurons (DA neurons) in rat subtantia nigra during its development.Methods Continuous coronal sections were made from perinatal rat midbrains embedded in paraffin. Tyrosine hydroxylase (TH) immunostaining technique was used to determine the DA neurons. Nissl staining method was used to delineate the extent of the substantia nigra of the rats from its 13th embryonic day (E13) to the 14th postnatal day (P14). The sections were examined under microscope, and the morphological indexes of the positive cells were measured by cytometric method.Results TH positive (TH ) neurons in the developing rat midbrain was first noticed in the ventral midbrain on E13 and reached the climax in number and density on E16. The number of TH neurons then decreased with development. By P14, the distribution and density of the TH neurons resembled that of the DA neurons in the adult. During the embryonic period, most of the neurons were round or ovoid in shape, with their processes becoming longer in length and denser in branches. After birth, the TH neurons gradually acquired all of the morphological features of their mature partners.Conclusion The genesis and development of the DA neurons in the substantia nigra of rat proceed in the perinatal period. A big number of DA neurons are first generated. Then the number of these cells begins to decrease, while the morphological features are maturing gradually. The distribution and morphological changes of the DA neurons will be completed on P14.