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.     

Neural substrates for episodic encoding and recognition of unfamiliar faces

Functional MRI was used to investigate brain activation in healthy volunteers during encoding of unfamiliar faces as well as during correct recognition of newly learned faces (CR) compared to correct identification of distractor faces (CF), missed alarms (not recognizing previously presented faces, MA), and false alarms (incorrectly recognizing newly presented faces, FA). Encoding was associated with frontal, occipital/fusiform, thalamic, and cerebellar activation. CR produced activation in frontal and cerebellar regions, whereas CF activated frontal and occipitotemporal regions as well as the thalamus. In contrast, MA was associated with frontal and thalamic activation, and FA with frontal activation. The CR minus CF comparison showed left lateral prefrontal and parietal activation, while no suprathreshold positive signal changes were detected when subtracting the other conditions (CR minus MA, CR minus FA, and vice versa). These results support the view that the successful episodic retrieval of newly learned faces is based on a dorsal visual stream mechanism.     

Hypothalamo-Pituitary-Adrenocortical Regulation Following Lesions of the Central Nucleus of the Amygdala

Previous reports indicate that the central nucleus of the amygdala (CeA) stimulates adrenocorticotropin and corticosterone secretion, suggesting a role for this region in central hypothalamo-pituitary-adrenocortical (HPA) stress regulation. To evaluate this hypothesis, this study assessed the impact of CeA lesion on the response of hypophysiotrophic paraventricular nucleus (PVN) neurons to acute restraint and chronic unpredictable stress exposure. In contrast to previous reports, CeA lesions did not affect corticosterone or ACTH secretion induced by acute stress. Acute restraint increased PVN corticotropin releasing hormone (CRH) mRNA expression, increased the number of parvocellular PVN neurons expressing the co-secretagogue arginine vasopressin (AVP), and induced cFOS mRNA expression in the parvocellular PVN. However, there was no additional effect of CeA lesion on any measure of PVN activation. Chronic unpredictable stress exposure induced long-term activation of the HPA axis, noted by thymic involution, adrenal hypertrophy and increased PVN CRH mRNA expression. Stress-induced changes in thymus and adrenal weights were not affected by CeA lesion. Further, CeA lesion rats did not differ from controls in post-stress CRH mRNA expression. However, basal CRH mRNA expression was increased in the PVN of CeA rats, suggesting that the CeA plays a role in long-term inhibition of the PVN. The results of these studies are not consistent with the hypothesis that the CeA is necessary for stress-induced pituitary-adrenocortical activation. Rather, this region may play a stressor-specific modulatory role in regulation of HPA function.     

Somatoforme Schmerzstörung am Beispiel des chronischen Unterbauchschmerzes der Frau

In this review we discuss the psychological dimension of chronic pelvic pain in women. We give an overview of the psychopathology of the disease. The psychosomatic correlations of this complex syndrome are discussed. The diagnostic criteria of somatoform pain disorder are relevant for a large number of patients. The psychotherapeutic approaches are described. Psychosomatic knowledge is very helpful in the management of chronic pelvic pain in women. It helps to avoid unnecessary operations and contributes to a satisfying doctor-patient-relationship.     

The neural regions sustaining episodic encoding and recognition of objects

In this functional MRI experiment, encoding of objects was associated with activation in left ventrolateral prefrontal/insular and right dorsolateral prefrontal and fusiform regions as well as in the left putamen. By contrast, correct recognition of previously learned objects (R judgments) produced activation in left superior frontal, bilateral inferior frontal, and right cerebellar regions, whereas correct rejection of distractor objects (N judgments) was associated with activation in bilateral prefrontal and anterior cingulate cortices, in right parietal and cerebellar regions, in the left putamen, and in the right caudate nucleus. The R minus N comparison showed activation in the left lateral prefrontal cortex and in bilateral cingulate cortices and precunei, while the N minus R comparison did not reveal any positive signal change. These results support the view that similar regions of the frontal lobe are involved in episodic encoding and retrieval processes, and that the successful episodic retrieval of newly learned objects is mainly based on a frontoparietal network.