Thy-1 immunoreactivity distinguishes patches/striosomes from matrix in the early postnatal striatum of the rat.

At P0, P2 and P3, islands of increased density of Thy-1-immunoreactive (Thy-1-IR) material, which coincided with the islands of dense dopaminergic axons, were noted in the striatum. By P5, the distribution of Thy-1-IR material was homogeneous throughout the developing striatum, but islands of dense dopaminergic axons persisted. The pattern of appearance of Thy-1, which is involved in extension of neurites and stabilization of synapses, suggests that it is involved in formation of connections between the substantia nigra and striatum in the developing rat brain.