Expression of D5 dopamine receptors in the walls of the lateral ventricles during the post-weaning rat development

Abstract

Even before the first synapses appear, neurotransmitters and their receptors are present in the developing brain regulating the cell fate of neuronal progenitors in neurogenic niches, such as the lateral ventricle. In particular, dopamine appears to play a pivotal role in the neurogenesis of the subventricular zone by controlling the proliferation and differentiation of progenitors through activation of different receptors. Although, dopamine receptor 5 (D5R) is expressed prenatally, there is little information regarding its role in either pre- or postnatal forebrain development. To examine the role of D5Rs on neurogenesis in the rat lateral ventricle subventricular zone (V-SVZ), we defined immunohistochemically D5R expression as well as BrdU incorporation in progenitor cells of various post-weaning stages (Post-natal day (P) 20 until P80). We found that the level of proliferating cells is stable from postnatal day 20 until 50 and then sharply declines on P80. Concomitantly, D5R is expressed in all ages examined, but we detected a progressive decrease in the density of D5R+ cells from P40 until P80. Moreover, double immunostaining for BrdU and D5R, revealed that proliferating cells in V-SVZ also express the D5R. Collectively, our data suggest that D5R is expressed in the post-weaning V-SVZ of rat at least until P80 and its expression pattern coincides that of proliferating cells in the V-SVZ, hinting to a possible role of D5Rs in the regulation of neuronal progenitor division/differentiation.