Grant: CIHR Fellowship

Postpartum depression (PPD) affects ~15% of women after giving birth but the causes of PPD are not fully understood. There is significant clinical overlap between women who discontinue breastfeeding and women who are diagnosed with PPD. It is possible that elimination of breastfeeding increases the risk for PPD. The proposed studies are designed to investigate the behavioural and brain consequences of disrupted lactation in a rat model of PPD. First, female rats will undergo surgery to prevent lactation (called a galactophore cut). Control rats will undergo sham surgery. Rats will then be mated and after giving birth, assessed for depressive-like behaviours and brain plasticity, which have been consistently associated with depression. Oxytocin is a hormone known for its role in milk let down, social bonding, and maternal behaviour. Lactation or nursing behaviours increase brain levels of oxytocin. If disrupted lactation induces depressive-like behaviours and alters hippocampal plasticity, then oxytocin may be involved. The following two studies will determine the role of oxytocin in depressive-like behaviour induced by disrupted lactation. Postpartum females will undergo conditions in which oxytocin levels are reduced (either through surgery or through drug treatment) to determine whether oxytocin levels are important for the development of depressive-like symptoms. Dams will be assessed for depressive-like behaviors and hippocampal plasticity. I hypothesize that disrupted oxytocin will induce depressive-like behaviours and alter hippocampal plasticity consistent with other animal models of depression. Further, oxytocin will reverse these changes. Collectively, this research will identify whether oxytocin levels in the brain play a role in PPD. This research will be important for discovering new treatments for women who develop PPD.