大鼠腹侧中脑多巴胺能神经元的形态学发育与分布特征

目的:探讨大鼠腹侧中脑多巴胺能(mDA)神经元的形态学发育和分布特征。方法:取胚胎晚期至成年大鼠不同时期的腹侧中脑连续冠状切片,以酪氨酸羟化酶(TH)免疫荧光染色方法观察mDA神经元。结果:(1)在胚胎期,TH阳性细胞多为圆形或椭圆形,随着发育进程,其突起逐渐伸长,分支也逐渐增多;出生后28 d,TH阳性细胞表现为成熟mDA神经元的形态特征。(2)Map-2/TH免疫荧光检测显示,新生期大鼠腹侧中脑TH阳性神经元定位分布与成年期的mDA神经元分布趋向一致。(3)E16.5 d时腹侧中脑TH阳性细胞的数量和密度最大,此后逐渐下降。结论:大鼠mDA神经元的发育在出生前后,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P0 d时mDA神经元分布定位基本完成,至出生后28 d形态学发育成熟。

The morphological changes and distributing features of dopaminergic neurons in rat ventral mesencephalon during its development

Objective: To explore the morphological changes and distributing features of mesencephalic dopaminergic(mDA) neurons in rat ventral mesencephalon(VM) during its development.Methods: Continuous coronal sections of rat VM were made from the embryonic period to adult.Tyrosine hydroxylase(TH) immunofluorescence histochemical staining technique was used to determine the mDA neurons.Results:(1) During the embryonic period,most of the TH positive neurons were round or ovoid in shape,with their processes becoming longer in length and denser in branches.By P28,the TH-positive neurons gradually acquired all of the morphological features of their mature mDA neurons.(2) Immunofluorescence histochemical staining for Map-2/TH showed the distribution of TH-positive neurons in P0 rat mesencephalon was almost coincident with mDA neurons in adult.(3) TH-positive neurons reached the climax in number and density on E16.5 in the developing VM of rat.The number and density of TH-positive neurons then decreased with development.Conclusion: The development of the mDA neurons in the mesencephalon of rat proceed in the perinatal period.A big number of mDA neurons are generated at the beginning,then the number of these cells begins to decrease,while the morphological features are maturing gradually.The distribution of the mDA neurons will be completed on P0,the morphological development will be completed on P28.