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.     

LOGICAL ANALYSES OF VIPASSANĀ MEDITATION

ABSTRACT

In this paper we propose logical analyses of Vipassanā Meditation as modus ponens or universal instantiation, as based upon identification, analysis, and interpretation of the meditation as a (spiritual) thought experiment (STE like e.g. huàtóus and kōans in Chan and Zen).*

The analyses consist in completing the unfinished enthymematic argument of the Sutta-nipāta by explication of hidden major. We speculate the thought experiment inference might be brought about by a faculty like mindfulness. The thought experiment analyses link the meditation to global cross-cultural theories and arguments in philosophy as Ibn Sīnā’s Flying Man and, notably, René Descartes’s Cogito. Last, we will give some indications how Vipassanā Meditation may be explained with help of western theories of consciousness.     

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.     

Would we rather lose our life than lose our self? Lessons from the Dutch debate on euthanasia for patients with dementia

This article reviews the Dutch societal debate on euthanasia/assisted suicide in dementia cases, specifically Alzheimer's disease. It discusses the ethical and practical dilemmas created by euthanasia requests in advance directives and the related inconsistencies in the Dutch legal regulations regarding euthanasia/assisted suicide. After an initial focus on euthanasia in advanced dementia, the actual debate concentrates on making euthanasia/assisted suicide possible in the very early stages of dementia. A review of the few known cases of assisted suicide of people with so-called early dementia raises the question why requests for euthanasia/assisted suicide from patients in the early stage of (late onset) Alzheimer's disease are virtually non-existent. In response to this question two explanations are offered. It is concluded that, in addition to a moral discussion on the limits of anticipatory choices, there is an urgent need to develop research into the patient's perspective with regard to medical treatment and care-giving in dementia, including end-of-life care.