| Febrile responsiveness of vagotomized rats is suppressed even in the absence of malnutrition. | |
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MedLine Citation:
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PMID: 9277568 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The repeatedly observed attenuation of fever in vagotomized rats has been accepted as evidence of an essential role of vagal afferents in the transduction of pyrogenic signals from the periphery to the brain. If, however, the general condition of a vagotomized animal is poor (the usual case) and accompanied by malnutrition and body mass loss (common complications of vagotomy), the febrile responsiveness can be suppressed not because of the lack of vagal afferentation, but rather secondarily to a malnutrition-associated thermogenic incompetence. In the present study, we addressed this dilemma. Male Wistar rats were subjected to subdiaphragmatic vagotomy (or sham surgery) and, 24 days later, catheterized in the jugular vein. Postsurgically, the rats were closely watched and fed highly palatable food. Their febrile responsiveness [colonic (Tc) and tail skin (Tsk) temperature responses] to Escherichia coli lipopolysaccharide (LPS: 1 microgram/kg i.v.) was tested on day 27 postvagotomy. To verify the completeness of vagotomy, each rat was food deprived for 24 h and then euthanized; its stomach's evacuatory function was assessed by weighing the organ. One month postsurgery, both food consumption and body mass of the vagotomized rats (33 +/- 2 g/day and 313 +/- 4 g, respectively) were similar to the control values (30 +/- 1 g/day and 315 +/- 8 g). In the sham rats, LPS induced a monophasic Tc rise of 0.5 +/- 0.3 degree C at 70 min postinjection (peak), preceded by a fall in Tsk. Neither this Tsk fall (tail skin vasoconstriction) nor the resultant fever occurred in the vagotomized rats; at 70 min, Tc change was -0.1 +/-0.1 degree C. The gastric mass (4.1 +/- 0.5 g in the vagotomized vs. 1.8 +/- 0.1 g in sham rats) indicated the effectiveness of vagotomy. In sum, although the vagotomy-associated malnutrition was successfully prevented with special perioperative care, the vagotomized animals still did not respond to LPS with fever. Malnutrition is, therefore, unlikely to constitute the main reason of the febrile irresponsiveness of vagotomized rats. |
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Authors:
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A A Romanovsky; V A Kulchitsky; C T Simons; N Sugimoto; M Székely |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The American journal of physiology Volume: 273 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1997 Aug |
Date Detail:
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Created Date: 1997-09-25 Completed Date: 1997-09-25 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: R777-83 Citation Subset: IM |
Affiliation:
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Thermoregulation Laboratory, Legacy Portland Hospitals, Oregon 97227, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Body Temperature / drug effects Fever / chemically induced*, physiopathology Health Status Injections, Intravenous Lipopolysaccharides* Male Nutrition Disorders / physiopathology* Rats Rats, Wistar Reference Values Sodium Chloride / pharmacology Vagotomy* |
| Chemical | |
Reg. No./Substance:
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0/Lipopolysaccharides; 7647-14-5/Sodium Chloride |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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