Fig. 9.

KDAC inhibitor AK-7 influences Arc protein level in vivo. a Experimental design used to assess the influence of AK-7 on Arc protein expression in mice dentate gyrus exposed to a familiar (home cage) or novel environment. b–e Representative captures of Arc immunostaining in the dentate gyrus of mice 3 h after intraperitoneal injection of vehicle (b, c) or AK-7 (d, e, 30 mg kg⁻¹). Scale bar 250 µm. Mice were returned to their home cage immediately after the injection and left undisturbed for the time period before killing. High-magnification image of the area highlighted by a dotted square in b, d are presented in c, e, respectively. Scale bar 50 µm. f, g Quantification of number of immunopositive Arc cells per mm² for the whole dentate gyrus of mice injected with vehicle or AK-7 and returned to their home cage (f) and average Arc immunofluorescence signal intensity in cell bodies (g). Data represent average made from three mice for each experimental condition. **p < 0.01, two-tailed t-test. h–k Representative captures of Arc immunostaining in the dentate gyrus of mice treated as in b–e but that were placed in a novel environment for 3 h immediately after the vehicle (h, i) or AK-7 (j, k) injection. Strong Arc expression caused by novel environment exposure can be observed in both conditions. l, m Quantification of number of Arc immunopositive cells per mm² in dentate gyrus reveals that no difference between the two injection groups for mice exposed to a novel environment (p = 0.571, two-tailed t-test) but quantification of Arc immunofluorescence in cell bodies was significant. ****p < 0.0001, two-tailed t-test. Data represent average made from three mice for each experimental condition. Dentate gyrus boundaries in each tissue section (with line) was segmented according to DAPI staining