Brain mRNA expression of proinflammatory cytokines, but not sickness behavior, is increased by intracerebroventricular lipopolysaccharide. Both wild-type (WT) and indoleamine-2,3-dioxygenase (IDO1) knockout (KO) mice exhibit increased steady-state mRNA expression of ( a ) IL-1β and ( b ) TNFα, but not of ( c ) <t>IL-6</t> in the whole brain 24 hours post intracerebroventricular (ICV) lipopolysaccharide (LPS, 10 ng). Exploratory locomotor activity measured by ( d ) distance traveled or ( e ) duration of time during the test spent moving were not different 24 hours after ICV LPS. Data are average ± standard error of the mean. n = 4 to 5 mice per group.
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