Fig. 8.

Effect of restraint stress and selective CRF₂ receptor blockade on PPI. Values shown are mean ± SEMs. For all groups, n = 8–9. The average of all prepulse stimulus intensities (76, 82, 85, and 88 dB) is shown as Percent Prepulse Inhibition. X-axis shows Pretreatment (ICV infusion)/Treatment (absence or presence of restraint). Rats received an ICV infusion of 10.0 µg ASV-30 (in 5.0 µl saline) or 5.0 µl saline. Ten minutes later, rats were restrained for 2 hours or were handled briefly and returned to the home cage. Rats were subjected to infusion and restraint (or brief handling) once a day for 5 consecutive days. Rats were tested for PPI 30 minutes after restraint termination on days 1, 3, and 5. (a) On day 1, neither pretreatment with ASV-30 nor restraint altered PPI. (b) On day 3, restraint attenuated the decrease in PPI caused by repeated testing (*p < 0.05 vs. No Restraint, main effect). ASV-30 pretreatment did not alter the effect of restraint on PPI on day 3. (c) On day 5, restraint decreased PPI only in rats that received ICV saline, as a significant difference was present between the SAL/NO RESTRAINT and SAL/RESTRAINT groups (*p = 0.018) and was absent (NS) between the ASV/NO RESTRAINT and ASV/RESTRAINT groups (separate two-way ANOVAs). Thus, ASV-30 pretreatment blocked the restraint-induced decrease in PPI on day 5 of restraint.