Chronobiologic factors in experimental stress ulcer

High self-esteem, hardiness and affective stability are associated with higher basal pituitary-adrenal hormone levels

Whereas much is known about the function of the hypothalamic-pituitary-adrenal (HPA) axis during environmental stress and in psychiatric disorders, little is known about the relation of individual differences in basal HPA-functioning to individual differences in healthy psychological functioning. In the present study, we recruited 37 healthy young men and examined the relations of hardiness, self-esteem and hypomanic personality--dispositions that moderate the effects of psychosocial stress on depressive reactions and health--to circulating levels of cortisol and beta-endorphin at rest. High self-esteem, hardiness and affective stability were associated with higher plasma cortisol levels and less psychological distress. Additionally, affective stability was associated with higher levels of beta-endorphin. The present findings suggest that individual differences in basal HPA-function are associated with individual differences in psychological functioning following stress.

The peptidergic brain-gut axis: influence on gastric ulcer formation

The existence of a relationship between the brain and the formation of gastric ulcers has been suspected since the last century. The advancement of stereotaxic procedures and the use of electrical lesion or stimulation have allowed localization within the limbic system, hypothalamus and brain stem, of discrete nuclei that influence the formation of gastric ulceration in experimental animals. Recently, further progress in the understanding of how the brain may influence gastric pathogenesis has been made by the demonstration that specific peptides act in the central nervous system to induce or prevent the formation of gastric ulcers and to markedly alter gastric secretory and motor function. Peptides established to have a centrally mediated protective effect are bombesin, calcitonin, corticotropin-releasing factor, neurotensin and opioid peptides. Growing evidence suggests a possible role for endogenous thyroptropin-releasing hormone in mediating cold-restraint stress induced gastric lesions. Circadian variations of the content and release of these peptides have been demonstrated in specific brain structures. To what extent such rhythms of peptide secretion are potentially linked to the circadian changes in the susceptibility to ulcer formation is worth investigating.