Ghrelin prevents lethality in a rat endotoxemic model through central effects on the vagal pathway and adenosine A2B signaling : Brain ghrelin and anti-septic action.
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引用次数: 0
Abstract
Accumulating evidence suggest that ghrelin plays a role as an antiseptic peptide. The present study aimed to clarify whether the brain may be implicated ghrelin's antiseptic action. We examined the effect of brain ghrelin on survival in a novel endotoxemic model achieved by treating rats with lipopolysaccharide (LPS) and colchicine. The observation of survival stopped three days after chemicals' injection or at death. Intracisternal ghrelin dose-dependently reduced lethality in the endotoxemic model; meanwhile, neither intraperitoneal injection of ghrelin nor intracisternal des-acyl-ghrelin injection affected the mortality rate. The brain ghrelin-induced lethality reduction was significantly blocked by surgical vagotomy. Moreover, intracisternal injection of a ghrelin receptor antagonist blocked the improved survival achieved by intracisternal ghrelin injection or intravenous 2-deoxy-d-glucose administration. Intracisternal injection of an adenosine A2B receptor agonist reduced the lethality and the ghrelin-induced improvement of survival was blocked by adenosine A2B receptor antagonist. I addition, intracisternal ghrelin significantly blocked the colonic hyperpermeability produced by LPS and colchicine. These results suggest that ghrelin acts centrally to reduce endotoxemic lethality. Accordingly, activation of the vagal pathway and adenosine A2B receptors in the brain may be implicated in the ghrelin-induced increased survival. Since the efferent vagus nerve mediates anti-inflammatory mechanisms, we speculate that the vagal cholinergic anti-inflammatory pathway is implicated in the decreased septic lethality caused by brain ghrelin.
期刊介绍:
The Journal of Physiology and Biochemistry publishes original research articles and reviews describing relevant new observations on molecular, biochemical and cellular mechanisms involved in human physiology. All areas of the physiology are covered. Special emphasis is placed on the integration of those levels in the whole-organism. The Journal of Physiology and Biochemistry also welcomes articles on molecular nutrition and metabolism studies, and works related to the genomic or proteomic bases of the physiological functions. Descriptive manuscripts about physiological/biochemical processes or clinical manuscripts will not be considered. The journal will not accept manuscripts testing effects of animal or plant extracts.