Figure 5.

Cytokine expression (mRNA levels of tumor necrosis factor alpha [TNFα], Interleukin-1β [IL-1], and interleukin-6 [IL-6], obtained via RT-PCR) in the hippocampus, amygdala, and paraventricular nucleus of the hypothalamus of male Sprague Dawley rats. During the conditioning, the rats were given four pairings between lemon odor and the post-absorptive effects of ethanol (2.0 g/kg, either intraperitoneally [i.p.] or intragastrically [i.g.]) or vehicle. Unpaired controls were given unrelated exposure between these stimuli. On test day, all animals were given 0.5 g/kg ethanol (i.p. or i.g., depending on the mode of ethanol administration used during conditioning) before a 3-h exposure to the lemon odor. Brain samples were taken thereafter. All data are normalized to glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and expressed relative to the unpaired-vehicle group corresponding to each mode of administration (i.e. i.p. or i.g). The pound signs in Panels C and F indicate that paired IP animals exhibited significantly greater mRNA levels of IL-6 at hippocampus and amygdala than unpaired counterparts (p < 0.05). The pound sign in Panel A indicates that, independent of the mode of administration, ethanol-treated paired rats exhibited greater TNFα in test at hippocampus than ethanol-treated unpaired rats. The pound sign in Panel B indicates that paired i.g. rats, ethanol- and vehicle-treated, exhibited significantly greater IL-1β levels in the hippocampus than the rest of the groups. The asterisk sign in Panel A indicates that TNFα levels in hippocampus were lower in ethanol-treated animals given the drug i.p. than in those given the drug. i.g. The ampersand sign in Panel D indicates that TNFα levels in amydgala were lower in rats, paired or unpaired and given ethanol or vehicle, that were given i.g. administrations. The ampersand sign in Panel I indicates greater IL-6 mRNA in those rats, paired or unpaired and treated with ethanol or vehicle, given i.g. intubations. The asterisk in panel G indicates that intraperitoneal, but not intragastric, ethanol treatment significantly decreased TNFα levels in the paraventricular nucleus. The error bar indicates SEM