Effects of intraperitoneal administration of saline (A, C) and LPS (B, D) (100 μg/kg body weight) on hippocampal extracellular levels of 5-HT (% of baseline; triangles) and behavioral activity (arbitrary units; bars) in long-term intracerebroventricularly vehicle-infused rats (A, B) and intracerebroventricularly CRH-infused rats (C, D) (Protocol B). For more details see Materials and Methods and legend to Figure 4. Values represent mean ± SEM (n = 5–7). For statistical analyses, see Results.