Lack of circadian fluctuation of anxiety-like behavior in SST deficient mice.

<p>(A) SST^-/- mice displayed hyperactivity during the second half of their active phase as indicated by total distance walked in the open field, compared to their SST+/+ littermates. (B) However, time spent in center did not differ between genotypes are time of testing. (C,D) In the light/dark- avoidance test, SST^-/- mice showed reduced exploration of the light compartment, indicating increased anxiety-like behavior during the second half of the active phase. In fact the mutants failed to show a reduction of anxiety as seen in SST^+/+ mice, thus indicating a deficit in the circadian modulation of anxiety- like behavior. Values are mean ± SEM. * significant differences between time point of testing, p<0.05; #, significant differences between SST^-/- and SST^+/+ mice, p < 0.05; # # p < 0.01.