Dopamine D2 receptor stimulation promotes the proliferation of neural progenitor cells in adult mouse hippocampus.

We initially examined the effects of apomorphine in vitro using mouse embryonic and adult neural progenitor cells. The effects of apomorphine treatment led to dose-dependent increases in the number of embryonic and adult neural progenitor cells, and dopamine D2 receptor antagonist treatment significantly reduced the increases induced by apomorphine. Next, we investigated the effects of apomorphine in vivo in the adult mouse hippocampus. The effects of single-dose apomorphine administration led to an increase of approximately 30% in the number of bromodeoxyuridine-positive cells in the dentate gyrus. Moreover, the chronic apomorphine administration induced an increase in the number of bromodeoxyuridine-positive cells by about 30%. Thus, we suggest that the stimulation of dopamine D2 receptors increases the proliferation of neural progenitor cells both in vivo and in vitro.