Figure 2.

Repeated propranolol pretreatment blocked repeated social defeat-induced anxiety-like behavior. Male C57BL/6 mice were injected subcutaneously with vehicle or propranolol (10 mg/kg) before each of the six cycles of SDR. Light/dark preference was determined 14 h after the sixth cycle of social defeat. A, Representative motion paths of the mice used in the light/dark testing paradigm. B, Average time to enter the dark zone. C, Average time spent in the dark zone. Bars represent the mean ± SEM (n = 10–16). Mice were treated as above. D, E, Spleen weight (D) and plasma IL-6 levels (E) were determined. Bars represent the mean ± SEM (n = 9). Means with different letters (a or b) are significantly different (p < 0.05) from each other.