Differences in psychosocial responses to pain between sufficiently and insufficiently active adults with arthritis

Objective: Adults with arthritis struggle to meet the physical activity recommendation for disease self-management. Identifying psychosocial factors that differentiate adults who meet (sufficiently active) or do not meet (insufficiently active) the recommendation is needed. This study sought to examine differences in psychosocial responses to arthritis pain among adults who were sufficiently or insufficiently active.

Design: This prospective study included adults with medically diagnosed arthritis (N = 136, M_age = 49.75 ± 13.88 years) who completed two online surveys: (1) baseline: pain and psychosocial responses to pain and (2) two weeks later: physical activity.

Main outcome measures: Psychosocial responses examined in this study were psychological flexibility in response to pain, pain anxiety and maladaptive responses to pain anxiety.

Results: A between-groups MANCOVA comparing sufficiently active (n = 87) to insufficiently active (n = 49) participants on psychosocial responses, after controlling for pain intensity, was significant (p = .005). Follow-up ANOVA’s revealed that sufficiently active participants reported significantly higher psychological flexibility and used maladaptive responses less often compared to insufficiently active participants (p’s < .05).

Conclusions: These findings provide preliminary insight into the psychosocial profile of adults at risk for nonadherence due to their responses to arthritis pain.     

Dissecting adrenal and behavioral responses to stress by targeted gene inactivation in mice

To define the molecular pathways modulating adrenal and behavioral responses to stress, we have generated mice with inactivation of hypothalamic neuropeptides and signaling pathways. Studies in mice deficient in corticotropin-releasing hormone (CRH) have revealed the essential role for CRH in adrenal glucocorticoid production in response to many physiological and psychological stressors. Immune system activation in CRH-deficient mice provides a unique exception to the necessity for CRH in stimulating adrenal glucocorticoid production. By analyzing mice deficient in interleukin-6 (IL-6) and CRH, we find that restoration of glucocorticoid output with inflammation is largely mediated by dysregulated IL-6 production. Current studies focus on identifying cellular and gene targets by which glucocorticoids regulate immune system function. In contrast to impaired adrenocortical responses to stress, CRH-deficient mice exhibit normal behavioral responses to stress. To determine signaling pathways that may contribute to the behavioral responses to stress, we have generated and analyzed mice deficient in adenylyl cyclase type 8 (AC8). AC8 deficient mice have intact adrenocortical responses to stress, but an inability to undergo stress-induced alterations in behavior.     

Analgesia induced by exposure to a novel environment in rats: effect of concurrent and post-training stressful stimulation

Exposure of rats for 2 min to a new environment (a 50 X 25 X 25-cm box) induced a mild analgesia measured by the tail-flick method. Additional stressful stimuli (0.5 mA, 1.5-s footshocks, light flashes, or tones) presented during the 2-min exposure did not alter the analgesia. However, the postexposure presentation of light flashes or tones, for either 10 s or 2 min, while the animals were alone in a waiting cage, prevented the analgesic response. Similarly, placing the subjects with their conspecifics in the home cage for 2 min after the exposure prevented the analgesic response. The data suggest that the analgesia may represent a physiological correlate of novelty and that the response can be impaired by post-training treatments.     

Differences between Saudi and U.S. students in reaction to same- and mixed-sex intimacy shown by others

U.S. and Saudi male and female students were shown 3 photos of 2 women sitting at a close, intermediate, and far distance from each other. Participants were then asked to imagine 2 sisters, 2 brothers, and a brother-sister team sitting at each of these 3 distances and to rate their comfort or discomfort with each scene. As predicted, the U.S. students felt more comfortable the farther away 2 brothers were sitting and the closer a brother and sister were sitting, whereas the Saudi students showed the opposite reaction. It was suggested that distances between the sexes in conservative Muslim countries is maintained even in intrafamily contact and that the aversion to public displays of male-male intimacy found in the United States and Europe does not generalize to other cultures.     

Temporal relationships between plasma cortisol, corticosteroid-binding globulin (CBG), and the free cortisol index (FCI) in pigs in response to adrenal stimulation or suppression

The objective of this study was to document changes in plasma concentrations of total cortisol, porcine corticosteroid-binding globulin (pCBG), and the free cortisol index (FCI) in pigs over a 6-h period in response to adrenal stimulation or suppression. Twenty-four 8-week old pigs allotted in equal numbers were administered ACTH, dexamethasone or saline, and blood samples were collected every 15 min via an indwelling jugular catheter for 1 h prior to and 5 h following treatment. Total plasma cortisol increased in ACTH-treated pigs and decreased in dexamethasone-treated pigs within 0.25 and 0.5 h, respectively. In contrast, pCBG concentration was altered in an inverse fashion subsequent to the changes exhibited in total cortisol. FCI reflected the changes observed in total cortisol. These results further document the negative relationship that exists between circulating concentrations of plasma cortisol and pCBG, and illustrate that this association exists under conditions of acute stress in the pig.