Prostaglandin mediates endotoxaemia‐induced hypophagia by activation of pro‐opiomelanocortin and corticotrophin‐releasing factor neurons in rats

Abstract

Corticotrophin-releasing factor (CRF) and α-melanocyte-stimulating hormone (α-MSH), both of which are synthesized by hypothalamic neurons, play an essential role in the control of energy homeostasis. Neuroendocrine and behavioural responses induced by lipopolyssacharide (LPS) have been shown to involve prostaglandin-mediated pathways. This study investigated the effects of prostaglandin on CRF and α-MSH neuronal activities in LPS-induced anorexia. Male Wistar rats were pretreated with indomethacin (10 mg kg −1 ; i.p.) or vehicle; 15 min later they received LPS (500 μg kg −1 ; i.p.) or saline injection. Food intake, hormone responses and Fos-CRF and Fos-α-MSH immunoreactivity in the paraventricular and arcuate nuclei, respectively, were evaluated. In comparison with saline treatment, LPS administration induced lower food intake and increased plasma ACTH and corticosterone levels, as well as an increase in Fos-CRF and Fos-α-MSH double-labelled neurons in vehicle-pretreated rats. In contrast, indomethacin treatment partly reversed the hypophagic effect, blunted the hormonal increase and blocked the Fos-CRF and Fos-α-MSH hypothalamic double labelling increase in response to the LPS stimulus. These data demonstrate that the activation of pro-opiomelanocortin and CRF hypothalamic neurons following LPS administration is at least partly mediated by the prostaglandin pathway and is likely to be involved in the modulation of feeding behaviour during endotoxaemia.

Systemic α-melanocyte-stimulating hormone administration decreases arthritis-induced anorexia and muscle wasting

“…POMC neurons of the ARC have IL-1␤ receptors, and IL-1␤ induced the expression of Fos protein in ARC POMC neurons and MSH release from hypothalamic explants (59). COX-2 activation is also involved in endotoxin-induced decrease in food intake and activation of hypothalamic POMC neurons (57). In arthritic rats ␣-MSH administration increased the anti-inflammatory cytokine IL-10.…”

Anti-inflammatory and antipyretic effects of Sonchus oleraceus in rats

“…Moreover, prostaglandins activate parenchymal elements of the brain during the acute-phase reaction of a systemic immunogenic challenge (Giusti-Paiva et al, 2003;Carnio et al, 2006;Rorato et al, 2009). The synthesis of prostaglandins plays a crucial role in the febrile response to endogenous pyrogens (such as the proinflammatory cytokines) or to exogenous pyrogens (such as lipopolisaccharide) (Blatteis et al, 2005).…”

Fluorescent Arc/Arg3.1 indicator mice: A versatile tool to study brain activity changes in vitro and in vivo

“…These d4EGFP-positive neurons expressed POMC, a key anorexic peptide in the brain (Coll and Loraine Tung, 2009), which is upregulated in the arcuate nucleus after LPS injection (Sergeyev et al, 2001). This suggests that Arc/Arg3.1 induction in these neurons contributes to LPS-induced anorexia (Rorato et al, 2009). In addition, these neurons are known targets for leptin (Scott et al, 2009).…”