HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 295/1/R361    most recent 00104.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Buchanan, J. B. Articles by Satinoff, E. PubMed PubMed Citation Articles by Buchanan, J. B. Articles by Satinoff, E.

TEMPERATURE AND FEVER

A warmer ambient temperature increases the passage of interleukin-1β into the brains of old rats

Department of Psychology and Program in Neuroscience, University of Delaware, Newark, Delaware

Submitted 13 February 2007 ; accepted in final form 24 April 2009

We have demonstrated that after intraperitoneal lipopolysaccharide (LPS) injection, old rats mount fevers similar to those of young rats at an ambient temperature (Ta) of 31°C, but not at 21°C. The same is true for intraperitoneal or intravenous IL-1β administration. The underlying mechanism responsible for blunted fever in old rats may be a deficiency in communication between the periphery and the brain. Possibly, peripheral cytokine actions are altered in old rats, such that the signal that reaches the brain is diminished. Here, we hypothesized that at standard laboratory temperatures, not enough IL-1β is reaching the brain for fever to occur and that a warmer Ta would increase the influx of IL-1β into the brain, enabling old rats to generate fever. Young (3–5 mo) and old (23–29 mo) Long-Evans rats were maintained for 3 days at either Ta 21 or 31°C prior to intravenous injection with radiolabeled IL-1β to measure passage across the blood-brain barrier. Young rats showed similar influx of IL-1β into the brain at the two Tas, but old rats showed significant influx only at the warmer Ta. These data suggest that the lack of fever at a cool Ta may be due to a reduced influx of IL-1β into the brain.

aging; blood-brain-barrier; cytokine; ambient temperature