title: Involvement of capsaicin-sensitive nerves in regulating the hormone and glucose metabolic response to endotoxin.
abstract: This study investigated the role that sensory nerves play in mediating the hormone and glucose metabolic response to endotoxin [lipopolysaccharide (LPS)]. Adult rats were pretreated subcutaneously with capsaicin to selectively destroy primary sensory afferent nerve fibers. Ten days later, [3-3H]glucose was infused intravenously to assess whole body glucose flux before and after the intravenous injection of Escherichia coli LPS (100 micrograms/100 g body wt). Control animals responded to LPS with characteristic increases in the plasma concentration of glucose (91%) and lactate (threefold) and elevations in the rates of glucose appearance and disappearance (77%). In capsaicin-treated rats, the maximal LPS-induced increase in these parameters was attenuated by 50-60%. In addition, these animals were hypoglycemic at the conclusion of the experiment. Control animals demonstrated early and sustained elevations in circulating levels of corticosterone, glucagon, and catecholamines. In contrast, the early LPS-induced elevation in epinephrine and norepinephrine, and to a lesser extent glucagon, was completely absent or greatly impaired by capsaicin pretreatment. In a separate study, the epinephrine-induced increase in glucose flux was blunted by 75% in capsaicin-treated rats. These data indicate that sensory afferent neurons play a critical role in the early secretory response of glucagon and catecholamines, the maintenance of tissue catecholamine responsiveness, and the stimulation of glucose production after LPS.
authors.affiliation: Department of Surgery, State University of New York at Stony Brook 11794-8191, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Morgan
authors.forename: C H
authors.initials: CH
authors.lastname: Lang
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D002211:Capsaicin / Q000494:pharmacology*; D004731:Endotoxins / Q000494:pharmacology*; D006439:Hemodynamics / Q000187:drug effects; D006728:Hormones / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D009420:Nervous System / Q000187:drug effects*; D009424:Nervous System Physiological Phenomena; D051381:Rats; D017207:Rats, Sprague-Dawley; D013312:Stress, Physiological / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D004731:Endotoxins; D006728:Hormones; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D002211:Capsaicin