Classical and nonclassical estrogen action in the developing midbrain

There is widespread acceptance that estrogen is involved in various steps o f cellular differentiation during brain development. In the past years, we have demonstrated such a developmental role for estrogen in the rodent midb rain. Precisely, estrogen affects midbrain dopamine neurons with respect to functional and morphological maturation. On the cellular level, estrogen m ay act classically by binding and activating its respective nuclear recepto rs, thereby controlling the transcription of target genes. On the other han d, many estrogen effects in the CNS are transmitted nonclassically by inter actions with putative membrane receptors and by stimulating distinct intrac ellular signaling cascades. In the midbrain, classical and nonclassical est rogen signaling routes operate side by side to ensure the proper developmen t of dopaminergic cells. In the present report, we detail some of the cellu lar and molecular events which are activated by estrogen and are thought to take part in the estrogen-mediated stimulation of dopamine neuron differen tiation. (C) 2001 Academic Press.