Opioidergic modulation of maternal behavior in rats: a role for progesterone - Cruz, A. M; Sukikara, Marcia Harumi; Felippe, Érika Cristiane Gutierrez; Anselmo-Franci, Janete Aparecida; Canteras, Newton Sabino; Oliveira, Cláudio Alvarenga de; Felicio, Luciano Freitas (Neuroscience Meeting Planner, 2011)