Figure 5.

Chronic up-regulation CRH and its receptor CRF₁ mRNAs in hippocampal CA3 pyramidal cells of 12-mo-old rats results from early-life administration of CRH. (A) Enhanced CRH mRNA expression in CA3 pyramidal cell layer (large arrowheads) in dark-field micrographs of emulsion-dipped sections from CRH-treated rats and controls. (Inset) Silver grains over an eccentrically located neuron (arrow) suggest CRH expression in nonpyramidal cells (interneurons). Small arrowhead points to an adjacent cell devoid of silver grains. (B) Semiquantitative analysis shows enhanced CRH mRNA levels in CA3A of CRH-treated rats. (C) CRF₁ mRNA is significantly up-regulated in CA3A and CA3C of CRH-treated rats. *, significant (P < 0.05) difference from vehicle and naive controls (one-way ANOVA with Tukey's analysis). CTL, control; so and sl, strata oriens and lucidum, respectively. [Scale bars = 100 μm (A) and 25 μm (Inset).]