Post-natal development of TH-like immunoreactivity in the rat retina.

The post-natal development of catecholaminergic neurons has been studied in the rat retina, using tyrosine-hydroxylase immunohistochemistry. The first TH-like immunoreactive cells were observed by the third post-natal day. The differentiation of neurons and the development of their processes continued until and after, the opening of the eyes (14-15th post-natal day). The catecholaminergic system was fully developed by three weeks of age. The use of retinal flat mounts treated with PAP-immunoperoxidase technique allowed a morphological observation of TH-like immunoreactive whole neurons.