investigation. Therefore, our correlational approach represents a no- vel tool to explore pain mechanisms beyond the current ‘‘all or none’’ studies. doi:10.1016/j.bbi.2011.07.055 53. Ex vivo IL-6 release and dexamethasone suppression in mononuclear cell cultures from postpartum women M. Groer University of South Florida College of Nursing, 12901 Bruce B Downs Blvd., Tampa, FL 33612, USA The hypothalamic–pituitary–adrenal axis (HPA) is profoundly altered during pregnancy due to high levels of placental corticotro- phin releasing hormone (CRH) and plasma cortisol. Placenta delivery is followed by a ‘‘resetting of glucocorticoid (GC) receptors’’ in all sensitive tissues. When this occurs, and how it affects stress and mood is not well characterized. Sensitivity of GC receptors was ana- lyzed through LPS-stimulated ex-vivo whole blood cultures with Dexamethasone in a range of concentrations in healthy women (n = 8–11) measured after birth at 1 week, 1 month, 2 months and 3 months. Supernatants were analyzed for Interleukin 6 (IL-6) and plasma was assayed for cortisol. Participants completed the Per- ceived Stress Scale (PSS) and Profile of Mood States (POMS) at each visit. Dexamethasone significantly inhibited IL-6 production at each time (p < .001). IL-6 production dropped steeply from the 1-week to the 1-month visit (p < .001), and then rose. Inhibition was greater at later time intervals. At 1-month plasma cortisol, depression and per- ceived stress were all higher than any other time. The significant de- crease in IL-6 at 1 month suggests rebound of GC receptors from pregnancy and 1-week to an upregulated state. This may represent an overshoot of the HPA. The phenomenon may help explain the pathophysiology of postpartum depression in some women, which peaks in incidence in the first 6 weeks of the postpartum. doi:10.1016/j.bbi.2011.07.056 54. Thyroid peroxidase antibody status is associated with depressive symptoms in pregnancy and the postpartum M. Groer, J. Heckel University of South Florida, College of Nursing, 18109 Emerald Bay Street, Tampa, FL 33647, USA The thyroid peroxidase antibody (TPO) is present in 10% of preg- nant women, half of whom will develop postpartum thyroiditis in the postpartum. A previous study had shown a relationship between postpartum depression and TPO positivity. Now we report confirma- tion of this, and the finding of the same relationship in pregnancy. Nearly 700 pregnant women were measured for the TPO antibody during weeks 16–25 of pregnancy. They completed a demographic instrument and the Profile of Mood States and the Perceived Stress scale at that time. The antibody was measured by ELISA and a value of greater than 20 IUs was considered positive. There was a signifi- cantly greater incidence of depression in TPO positive women during pregnancy. A subset of women were followed into the postpartum (N = 114) and visited monthly for 6 months. Over half the TPO posi- tive women developed thyroiditis during the postpartum, but regardless of this, there was a significantly higher incidence of depression in TPO positive compared to negative postpartum wo- men. These data support a relationship between autoimmune dis- ease and depression across the perinatal period that may be related to immune processes. doi:10.1016/j.bbi.2011.07.057 55. Chronic psychological stress affects terminal blood cell differentiation J.L. Voorhees a , T.D. Eubank a , B. Aguda b , C. Marsh a a The Ohio State University Department of Internal Medicine, #405 Davis Heart & Lung Research Institute, 473 W. 12th Ave., Columbus, OH 43210, USA b Mathematical Biosciences Institute, The Ohio State University, USA This project seeks to describe the biochemical mechanisms that direct terminal blood cell production and differentiation in response to chronic psychological stress. We have employed a model of murine restraint stress to demonstrate that in response to chronic restraint stress animals exhibited diminished lymphocyte, monocyte, neutro- phil, and total white blood cell production and increased reticulocyte production. These parabolic patterns of altered expression are affected on the order of weeks and show non-synchronous temporal patterns of onset, maximum response, and resolution. No altered trend in red blood cell accumulation was detected. Using genome-wide micro- array we have posited a coherent description of the altered molecular signaling events that underlie these changes in blood cell develop- ment at all stages, beginning at the level of hematopoietic progenitors and continuing through terminal differentiation. By monitoring changes in transcriptional regulators of hematopoiesis, we give evi- dence that in response to chronic stress animals experience a shift in the population distribution of progenitor cells resulting in decreased white blood cell precursors and increased erythrocyte precursors. Fur- ther, we suggest the reticulocytes that result from these erythrocytes are frequently released into circulation prematurely, resulting in hemolysis and preventing them from ultimately becoming mature red blood cells. Given the role of white blood cells in mounting effec- tive immune responses, understanding the role of prolonged stress in the process of hematopoiesis could hold great human significance. doi:10.1016/j.bbi.2011.07.058 56. Compartmentalized immune response in the barrel field of the mouse primary somatosensory cortex A. Chavarría a , J. Pérez-H a,b , P. Carrillo-Mora c , A. Santamaría c , G. Gutiérrez-Ospina d , R. Pérez-Tamayo a a Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Hospital General de México SSA, Dr. Balmis 148, Col. Doctores, Mexico City 06720, Mexico b Posgrado en Biología Experimental, Universidad Autónoma Metropol- itana, Mexico c Laboratorio de Aminoácidos Excitadores, Instituto Nacional de Neuro- logía y Neurocirugía SSA, Mexico d Departamento de Biologı ´a Celular y Fisiología, Instituto de Investigac- iones Biomédicas,Universidad Nacional Autónoma de México, Mexico Central Nervous System presents a heterogeneous immune response, probably due to the existence of immune compartments within, and their structural and functional association with neural modules. To explore this idea we used the model of the barrel field in the primary somatosensory cortex (S1) of adult CD1 mice. Lesions were performed inside the barrel field or in the dysgranular cortex next to it, S194 PNIRS meeting abstracts / Brain, Behavior, and Immunity 25 (2011) S179–S242