Transient Gastric Irritation in the Neonatal Rats Leads to Changes in Hypothalamic CRF Expression, Depression- and Anxiety-Like Behavior as Adults

A disturbance of the brain-gut axis is a prominent feature in functional bowel disorders (such as irritable bowel syndrome and functional dyspepsia) and psychological abnormalities are often implicated in their pathogenesis. We hypothesized that psychological morbidity in these conditions may result from gastrointestinal problems, rather than causing them.Functional dyspepsia was induced by neonatal gastric irritation in male rats. 10-day old male Sprague-Dawley rats received 0.1% iodoacetamide (IA) or vehicle by oral gavage for 6 days. At 8-10 weeks of age, rats were tested with sucrose preference and forced-swimming tests to examine depression-like behavior. Elevated plus maze, open field and light-dark box tests were used to test anxiety-like behaviors. ACTH and corticosterone responses to a minor stressor, saline injection, and hypothalamic CRF expression were also measured.Behavioral tests revealed changes of anxiety- and depression-like behaviors in IA-treated, but not control rats. As compared with controls, hypothalamic and amygdaloid CRF immunoreactivity, basal levels of plasma corticosterone and stress-induced ACTH were significantly higher in IA-treated rats. Gastric sensory ablation with resiniferatoxin had no effect on behaviors but treatment with CRF type 1 receptor antagonist, antalarmin, reversed the depression-like behavior in IA-treated ratsThe present results suggest that transient gastric irritation in the neonatal period can induce a long lasting increase in depression- and anxiety-like behaviors, increased expression of CRF in the hypothalamus, and an increased sensitivity of HPA axis to stress. The depression-like behavior may be mediated by the CRF1 receptor. These findings have significant implications for the pathogenesis of psychological co-morbidity in patients with functional bowel disorders

Reviewing the use of resilience concepts in forest sciences

Purpose of the review Resilience is a key concept to deal with an uncertain future in forestry. In recent years, it has received increasing attention from both research and practice. However, a common understanding of what resilience means in a forestry context, and how to operationalise it is lacking. Here, we conducted a systematic review of the recent forest science literature on resilience in the forestry context, synthesising how resilience is defined and assessed. Recent findings Based on a detailed review of 255 studies, we analysed how the concepts of engineering resilience, ecological resilience, and social-ecological resilience are used in forest sciences. A clear majority of the studies applied the concept of engineering resilience, quantifying resilience as the recovery time after a disturbance. The two most used indicators for engineering resilience were basal area increment and vegetation cover, whereas ecological resilience studies frequently focus on vegetation cover and tree density. In contrast, important social-ecological resilience indicators used in the literature are socio-economic diversity and stock of natural resources. In the context of global change, we expected an increase in studies adopting the more holistic social-ecological resilience concept, but this was not the observed trend. Summary Our analysis points to the nestedness of these three resilience concepts, suggesting that they are complementary rather than contradictory. It also means that the variety of resilience approaches does not need to be an obstacle for operationalisation of the concept. We provide guidance for choosing the most suitable resilience concept and indicators based on the management, disturbance and application context

Neuroanatomy of extrinsic afferents supplying the gastrointestinal tract

Here we discuss the neuroanatomy of extrinsic gastrointestinal (GI) afferent neurones, the relationship between structure and function and the role of afferents in disease. Three pathways connect the gut to the central nervous system: vagal afferents signal mainly from upper GI regions, pelvic afferents mainly from the colorectal region and splanchnic afferents from throughout. Vagal afferents mediate reflex regulation of gut function and behaviour, operating mainly at physiological levels. There are two major functional classes - tension receptors, responding to muscular contraction and distension, and mucosal receptors. The function of vagal endings correlates well with their anatomy: tracing studies show intramuscular arrays (IMAs) and intraganglionic laminar endings (IGLEs); IGLEs are now known to respond to tension. Functional mucosal receptors correlate with endings traced to the lamina propria. Pelvic afferents serve similar functions to vagal afferents, and additionally mediate both innocuous and noxious sensations. Splanchnic afferents comprise mucosal and stretch-sensitive afferents with low thresholds in addition to high-threshold serosal/mesenteric afferents suggesting diverse roles. IGLEs, probably of pelvic origin, have been identified recently in the rectum and respond similarly to gastric vagal IGLEs. Gastrointestinal afferents may be sensitized or inhibited by chemical mediators released from several cell types. Whether functional changes have anatomical correlates is not known, but it is likely that they underlie diseases involving visceral hypersensitivity.Berthoud, H R ; Blackshaw, L A ; Brookes, S J H ; Grundy,