Physiology & behavior
-
Physiology & behavior · Sep 2015
Male adolescent rats display blunted cytokine responses in the CNS after acute ethanol or lipopolysaccharide exposure.
Alcohol induces widespread changes in cytokine expression, with recent data from our laboratory having demonstrated that, during acute ethanol intoxication, adult rats exhibit consistent increases in interleukin (IL)-6 mRNA expression in several brain regions, while showing reductions in IL-1 and TNFα expression. Given evidence indicating that adolescence may be an ontogenetic period in which some neuroimmune processes and cells may not yet have fully matured, the purpose of the current experiments was to examine potential age differences in the central cytokine response of adolescent (P31-33days of age) and adult (69-71days of age) rats to either an acute immune (lipopolysaccharide; LPS) or non-immune challenge (ethanol). In Experiment 1, male Sprague-Dawley rats were given an intraperitoneal (i.p.) injection of either sterile saline, LPS (250μg/kg), or ethanol (4-g/kg), and then trunk blood and brain tissue were collected 3h later for measurement of blood ethanol concentrations (BECs), plasma endotoxin, and central mRNA expression of several immune-related gene targets. ⋯ Analysis of BECs indicated that, for both routes of exposure, adolescents exhibited lower BECs than adults. Taken together, these data suggest that categorically different mechanisms are involved in the central cytokine response to antigen exposure versus ethanol administration. Furthermore, these findings confirm once again that acute ethanol intoxication is a potent activator of brain cytokines, and calls for future studies to identify the mechanisms underlying age-related differences in the cytokine response observed during ethanol intoxication.