3beta hydroxy 5beta pregnan 20 one 2 4 aminobutyric acid A receptor 2 Chick optic lobe 2 Developing avian CNS 2 GABA(A) receptor complex 2 Neurosteroidogenesis 2 Neurosteroids 2 [C]Progesterone 2 [H]Flunitrazepam binding modulation 2 animal tissue 2 article 2 binding affinity 2 biosynthesis 2 carbon 14 2 central nervous system 2 chicken 2 controlled study 2 embryo 2 flunitrazepam 2 fowl 2 nervous system development 2 neurosteroid 2 nonhuman 2 optic lobe 2 pregnanedione 2 priority journal 2 progesterone 2 steroid metabolism 2 steroidogenesis 2