Differential expression of mRNAs for PACAP and its receptors during neural differentiation of embryonic stem cells.

Abstract The expressions of mRNAs for pituitary adenylate cyclase-activating polypeptide (PACAP), vasoactive intestinal peptide (VIP), and their receptors (PAC 1 , VPAC 1 and VPAC 2 ) were examined in the five steps of the in vitro neuronal culture model of embryonic stem (ES) cell differentiation. mRNAs for PACAP, VIP, PAC 1 receptor, and VPAC 2 receptor were moderately expressed in neural stem cell-enriched cultures, while VPAC 1 receptor mRNA was most prominently expressed in embryoid bodies (EBs). The expression of PAC 1 receptor mRNA was further upregulated after terminal differentiation into neurons. In contrast, the expressions of PAC 1 receptor and PACAP mRNAs were markedly decreased after glial differentiation. These results suggest that this in vitro neuronal culture system will be a useful model for future studies on the functional role of the PACAPergic system during different stages of neuronal development.