pathway. (Supported by NIH to KWK (R01 MH 51569 and R01 AG 029573) and RD (R01 MH 079829 and R01 MH 71349). doi:10.1016/j.bbi.2011.07.069 67. Sickness hurts: Human pain sensitivity in response to exper- imental inflammatory stimulation M. Lekander a,b , B. Karshikoff b , M. Ingvar b , E. Kosek b , A. Soop c , C. Olgart Höglund b,d,e , J. Axelsson b a Stress Research Institute, Stockholm University, Stockholm SE-106 91, Sweden b Osher Center for Integrative Medicine, Karolinska Institutet, Sweden c Department for Clinical Science, Intervention and Technology, Karo- linska Institutet, Sweden d Department of Medicine, Karolinska Institutet, Sweden e Department of Physiology and Pharmacology, Karolinska Institutet, Sweden The powerful pain facilitatory effects of a sickness response is well described in animals, but is little investigated in humans. In a randomized cross-over design, eight healthy participants (7 men, 1 woman, m = 24 years) were injected once with 0.8 ng/kg endotoxin (E. coli) and once with placebo. Tests of pain sensitivity were per- formed before, 90 and 270 min after injection. Thresholds for heat pain, induced on the ventral left forearm, were similar after injection with endotoxin as compared to placebo. Pressure pain sensitivity was assessed with pressure algometry on four bilateral sites. After endotoxin, the thresholds for pressure pain on these sites turned lower, so that less pressure was needed for a stimulation to be per- ceived as painful as compared to after placebo (p < .001). Lastly, endogenous pain modulation (diffuse noxious inhibitory controls; DNIC) was tested by measuring pressure pain thresholds before and after a secondary pain (cold pressor) was inflicted on the lower right arm. As expected, pressure pain thresholds were significantly higher after as compared to before application of cold pressor (p < .001), but were in general markedly lower in the endotoxin con- dition (p < .001). A pain inhibiting effect of cold pressor was present also after endotoxin, but appeared flattened. The present study dem- onstrates for the first time that human pain thresholds are affected by an experimental and relatively mild transient stimulation of the inflammatory system. doi:10.1016/j.bbi.2011.07.070 68. Chronic inflammation in the elderly is associated with increased tryptophan catabolism and altered phenylalanine turnover: Relevance for neuropsychiatric morbidity L. Capuron a , P. Barberger-Gateau b , S. Layé a , D. Fuchs c a INRA UMR 1286 University Bordeaux, Nutrition and Integrative Neurobiology, 146 rue Leo Saignat, Bordeaux 33076, France b INSERM U897, Bordeaux, France c Division of Biological Chemistry, Innsbruck, Austria Recent data suggest that chronic low-grade inflammation plays a role in the development of neuropsychiatric symptoms in the elderly. Effects may rely on the influence of inflammation on the activity of two enzymatic pathways, the indoleamine-2,3-dioxygen- ase (IDO) and the guanosine-triphosphate-cyclohydrolase-1 (GTP- CH1) pathways, which are involved in the biosynthesis of monoam- ines. The present study assessed this possibility in a sample of healthy elderly subjects drawn from the Three-City cohort. Partici- pants were submitted to a complete neuropsychiatric evaluation assessing mood, neurovegetative and general behavioral symptoms. In addition, blood samples were collected for the measurement of interleukin-6 and C-reactive-protein as inflammatory markers, tryp- tophan, kynurenine and their ratio as index of IDO activity, and neopterin, phenylalanine and tyrosine, as markers of GTP-CH1 activ- ity. As expected, age correlated significantly with concentrations of immune markers and neuropsychiatric symptoms. Increased inflam- mation was related to reduced tryptophan concentrations and increased kynurenine levels, suggestive of IDO-induced increased tryptophan catabolism. In addition, inflammation was associated with increases in neopterin and in phenylalanine concentrations, at the expense of tyrosine. Increased tryptophan catabolism corre- lated with depressive symptoms whereas alterations in phenylala- nine turnover associated with neurovegetative and general behavioral symptoms, including sleep disturbance, sickness and motor symptoms. These findings suggest that inflammation-related alterations in tryptophan and phenylalanine metabolism participate in the pathophysiology of neuropsychiatric symptoms in the elderly. doi:10.1016/j.bbi.2011.07.071 69. Aging, resources, and natural killer cell senescence S.C. Segerstrom, C.T. Lutz University of Kentucky, Psychology, 115 Kastle Hall, Lexington, KY 40506-0044, USA Immune senescence may increase risk for infectious and neoplas- tic disease. Senescence has recently been characterized in NK cells and identified with CD57 expression. The present study examined how psychosocial resources relate to CD57 on NK cells. Resources can reduce the likelihood and impact of stressors that may contrib- ute to premature immune aging. Young (21–31; N = 38) and elderly (74–97; N = 34) women completed the Conservation of Resources Evaluation and had blood drawn for evaluation of NK cell subsets: total NK, CD56bright, and CD56dim. Elderly women had a higher CD57+ percentage than young women in all NK subsets (all p < .05). More resources predicted a lower CD57+ percentage in total NK (Rsq = .08, p < .05), CD56dim (Rsq = .08, p < .05), and – in elderly women only – CD56bright (Rsq = .06, p < .05). Within the elderly wo- men, older age predicted a higher CD57+ percentage in total NK and CD56dim (both p < .05). Older women with more resources had few- er CD57+ cells in total NK (Rsq = .20, p < .01) and CD56dim (Rsq = .16, p < .05). One SD difference in resources was the equiva- lent of approximately five years of aging within the elderly women. Resources may protect against NK senescence by protecting against stress and limiting factors that drive NK activation and turnover, such as DNA damage and viral infection. doi:10.1016/j.bbi.2011.07.072 70. TNF-alpha mediated corticostriatal plasticity regulates the development of haloperidol-induced orofacial dyskinesia G. Lewitus a , M. St-Hilaire b , D. Stellwagen a a McGill University, 1650 Cedar Avenue, L12-132, Montreal, QC, Canada b Douglas Hospital Research Centre, Canada Antipsychotic drug (such as haloperidol) administration during the treatment of psychosis can produce a variety of undesirable S198 PNIRS meeting abstracts / Brain, Behavior, and Immunity 25 (2011) S179–S242