Aim of our study is to assess the effect of the histone-deacetylase inhibitor TSA and the cytoprotective PACAP on the survival and developmental rate of frozen/thawed embryos. Furthermore, we investigate the possibilities of the application of these chemicals in the assisted reproductive technologies. We assess the effect of endogenous PACAP on early embryo development, embryo quality and implantation rate using wild type, heterozygous and PACAP-KO mice.