“…Furthermore, there are indications of altered emotional behaviour in lactating rats (Hard & Hansen, 1984;Walker et al 1995). Besides the well-described stress responses of the HPA axis there is also activation of the hypothalamo-neurohypophysial system (HNS), releasing either oxytocin or vasopressin or both from the neurohypophysis into blood, in response to various stressors (Lang, Heil, Ganten, Hermann, Unger & Rascher, 1983;Kasting, 1988;Wotjak, Kubota, Ganster, Liebsch, Neumann & Landgraf, 1996). During lactation, the stimulated oxytocin secretion is reduced in response to physical stress (Carter & Lightman, 1987;Lightman, 1992;Neumann, Pittman & Landgraf, 1995b;Walker et al 1995) and hyperosmotic or pharmacological stimulation (Patel, Chowdrey & Lightman, 1991;Koehler, McLemore, Tang & Summy-Long, 1993;Neumann, Landgraf, Bauce & Pittman, 1995a).…”