Behavioural studies were performed using adult male wild type C57BL/6 or mutant strains maintained as previously described10 (link),15 (link). All drugs utilized were administered via intraperitonteal injection. Antidepressant-like behaviour was assessed using the forced swim test as previously described4 (link). Briefly, animals were placed in a cylinder of water (22-24° C) for 6 minutes and immobility was measured during the last 4 minutes of the test. Molecular studies consisted of Western blotting analysis or QPCR performed on whole cell lysates from medial prefrontal cortex or anterior HC. Electrophysiological studies were performed as previously described in cultured neurons (whole cell recordings23 (link)) or hippocampal slices (field recordings10 (link)).