The loss of VIP does not impact shock-evoked freezing or corticosterone response. A) WT and VIP-deficient mice were directly shocked with progressively increasing stimulus intensities and the freezing response measured. The measurement of these acute fear responses were conducted in the early day (ZT 3). The VIP-deficient mice exhibited more freezing in response to the lowest intensity shock (0.1 mA) but there were no differences between the genotypes at the other shock intensities. B) Corticosterone response to acute stress evoked by foot-shock (0.2 mA applied twice) in the early day (ZT3). Both WT and VIP-deficient mice displayed a significant induction of corticosterone in response to acute stress (P < 0.05). There were no significant differences between the two genotypes in the baseline or the evoked corticosterone levels.
Chaudhury et al. BMC Neuroscience 2008 9:63 doi:10.1186/1471-2202-9-63