Effects of Acute Stress or Centrally Injected Interleukin-1beta on Neuropeptide Expression in the Immune System

Acute stress stimulates the expression and release of corticotropin-releasing hormone (CRH) and arginine vasopressin (AVP) from the hypothalamus, and the pro-opiomelanocortin products beta-endorphin and ACTH from the anterior pituitary. These neuropeptides are also expressed in immune tissues, and it has been proposed that they may modulate immune responses to stress through paracrine mechanisms. We subjected rats to restraint stress or central injection of interleukin (IL)-1beta to determine whether these acute stimuli can alter the expression of neuropeptides in the spleen and thymus. Restraint stress significantly increased the contents of all these neuropeptides in thymic, but not splenic, extracts. A single icv injection of IL-1beta increased contents of CRH, AVP, ACTH and beta-endorphin in the spleens of both sham-operated and adrenalectomised (ADX) rats. IL-1beta increased thymic contents of CRH and ACTH in sham-operated rats but these increases were not observed in ADX rats. These results suggest that the effects of IL-1beta on neuropeptide expression in the spleen are independent of glucocorticoids, whereas IL-1beta stimulation of neuropeptide expression in the thymus is dependent on circulating glucocorticoids. There were significant correlations between increases in CRH, ACTH and beta-endorphin in the spleen, and between CRH and ACTH in the thymus, consistent with the suggestion that IL-1beta-induced increases in ACTH and beta-endorphin may be mediated through CRH. These results provide evidence that stressors can directly influence neuropeptide expression in immune tissues. Thus stress may influence immune functions through paracrine mechanisms involving locally synthesised neuropeptides as well as through activation of the hypothalamo-pituitary-adrenal axis.     

A comparison of dyadic interactions and coping with still‐face in healthy pre‐term and full‐term infants

Pre‐term birth has a significant impact on infants' social and emotional competence, however, little is known about regulatory processes in pre‐term mother‐infant dyads during normal or stressful interactions. The primary goals of this study were to investigate the differences in infant and caregiver interactive behaviour and dyadic coordination of clinically healthy pre‐term compared to full‐term infant‐mother dyads and to examine pre‐term infants' capacity for coping with stress using the face‐to‐face still‐face paradigm (FFSF). Fifty mother‐infant dyads, including 25 pre‐term infants and 25 full‐term infants were videotaped during the FFSF. All infants were 6–9 months of age (corrected for gestational age in the pre‐term group). Infant and maternal socio‐emotional expressivity and self‐regulatory behaviours were coded and measures of dyadic coordination (Matching, Reparation Rate, and Synchrony) were calculated. There were no significant differences in infant and caregiver socio‐emotional behaviours between the two groups and both groups demonstrated the still‐face (SF) effect and the reunion effect. There was a difference in self‐regulatory behaviour. Pre‐term infants were more likely than full‐term infants to use distancing (e.g., by turning away, twisting, or arching) from their mothers during the FFSF. Additionally, during the Reunion episode of the FFSF pre‐term infants showed more social monitoring compared to full‐term infants. Regardless of the birth status, the dyads showed less coordination and a slower rate of reparation during the Reunion episode than during the Play episode. The higher proportion of distancing in the pre‐term group and the increase in social monitoring suggest that even in normal interactions pre‐term infants may experience a higher level of stress and have less capacity for self‐regulation compared to the full‐terms and that pre‐term infants appear to use a compensatory strategy of increased social monitoring to cope with the stress of renegotiating the interaction during Reunion. The findings suggest that pre‐term infants have different regulatory and interactive capacities than full‐term infants.     

Regulation of Peripheral Catecholamine Responses to Acute Stress in Young Adult and Aged F-344 Rats

Young adult (3-month-old) and aged (24-month-old) Fischer-344 male rats received i.v. infusions of 3H-labeled norepinephrine (NE) and epinephrine (EPI) to examine the effects of aging on the neuronal uptake of NE and sympathoadrenal release of NE and EPI. Spillovers of NE and EPI into plasma and their clearance from the circulation were estimated from plasma concentrations of endogenous and 3H-labeled NE and EPI. The efficiency of neuronal uptake was assessed from changes in plasma clearance of NE and concentrations of its intraneuronal metabolite, dihydroxyphenylglycol (DHPG), during immobilization stress or neuronal uptake blockade with desipramine. Stress-induced increases in plasma NE and higher plasma NE concentrations in aged compared to young adult rats were due to both decreases in NE clearance and increases in NE spillover. EPI spillover and clearance were reduced in aged compared to young adult rats, so that plasma EPI levels did not differ between groups. Young adult and aged rats had similar desipramine-induced decreases in NE clearance, whereas desipramine-sensitive decreases and stress-induced increases in plasma DHPG were larger in aged rats. This indicates that neuronal uptake is intact and that increased NE spillover at rest and during stress in aged rats reflects increased NE release from sympathetic nerves. The results show that aging is associated with divergent decreases in EPI release from the adrenal medulla and increases in NE release from sympathetic nerves. Increased plasma concentrations of NE in aged compared to young adult rats also result from decreased circulatory clearance of NE, but this does not reflect any age-related impairment of NE reuptake.     

Effect of Nonspecific Chronic Low Back Pain on Walking Economy: An Observational Study

The authors investigated the effects of chronic low back pain (LBP) and walking speed (WS) on metabolic power and cost of transport (CT). Subjects with chronic nonspecific LBP (LBP group [LG]; n = 9) and healthy (control group [CG]; n = 9) were included. The test battery was divided into 3 blocks according to WS as follows: preferred self-selected speed (PS), and lower and higher than the PS. In each block, the volunteers walked 5 min, during which oxygen consumption was measured. Although without differences between groups, the LG had CT lower in slower speeds than in faster speeds. Walking speed affected CT only in the LG, which the group had the greatest walking economy at slower speeds.     

Coping responses and problem appraisal in Spanish adolescents

This study uses Moos's Coping Responses Inventory (Youth Form, 1993) to examine coping behavior in Spanish adolescents. 1362 adolescents were recruited from the metropolitan area of Barcelona, Spain. All subjects were in high school and ages 12 to 16 years. The socio-economic status was primarily middle class. Adolescents' coping behaviors were examined by sex and age, and the relationship between problem appraisal and choice of coping strategy was analyzed. Girls used more approach, avoidance, and behavioral responses than boys, especially Logical Analysis, Seeking Guidance and Support, and Emotional Discharge strategies. At older ages, Logical Analysis and Emotional Discharge became more frequent in girls and Cognitive Avoidance less frequent in boys. The results also suggest that problem appraisal has only a limited effect on the selection of coping strategies and that only few strategies are related to the problems' outcomes.     

Psychometric properties of the Coping Response Inventory with Brazilian adolescents

To analyze the psychometric properties of the Coping Response Inventory-Youth Form (CRI-Y) and its applicability, 426 Brazilian adolescents (43.3% boys, 56.7% girls), ages 12 to 18 years (M = 16.5, SD = 1.6), completed the authorized Brazilian/Portuguese version of the 1993 original. Analysis showed higher use of Approach coping and Emotional Discharge by the girls. The inventory showed internal consistency reliability was similar to that of the original scale. A two-factor structure reflecting Approach and Avoidance coping was found; however, the distribution of loadings of specific coping scales on this two-factor structure did not fit the original Moos model. The criterion validity analyzed by the use of the Youth Self-Report showed significant positive relation between the Avoidance dimension and Psychopathological symptoms for boys and girls. Data were discussed with respect to coping theory, assessment, and cultural influences.