CLDN5 and Anxiety: Intra-hippocampal injection of 0.3 μg kainic acid for 3 h (acute) and 4 weeks (chronic) resulted in distinct behavioural abnormalities in mice that we have previously reported in claudin-5-deficient animals with increased anxiety and hyperlocomotion as assessed by distance travelled and the number of entries to the centre zone in the open field test (Fig. 2a and Supplementary Fig. 2a).