Interleukin-1 beta alters brown adipose tissue but not renal sympathetic nerve responses to hypothermia.
Proinflammatory cytokines and acute physical stress influence sympathetic nerve discharge (SND). Because interleukin-1 beta (IL-1 beta) produces physiological responses that require central neural integration and because the sympathetic nervous system mediates physiological responses to environmental stress, we hypothesized that IL-1 beta modulates SND responses to acute physical stress. Therefore, this study examined the effects of IL-1 beta (290 ng/kg iv) and mild hypothermia on renal and interscapular brown adipose tissue (IBAT) SND regulation in chloralose-anesthetized rats. IBAT SND did not change after IL-1 beta administration but was significantly increased during acute mild hypothermia, which was induced 60 min after IL-1 beta treatment. Renal SND was unchanged after IL-1 beta administration and during hypothermia. Acute hypothermia, without prior IL-1 beta administration, did not alter IBAT and renal SND. Increases in IBAT SND during sustained (120 min) hypothermia were significantly higher in IL-1 beta-treated rats compared with saline-treated rats, whereas renal SND responses to sustained hypothermia did not differ among groups. Exposure to acute cold stress after sustained hypothermia produced greater increases in IBAT SND in IL-1 beta-treated rats compared with saline-treated controls. These data suggest that IL-1 beta alters IBAT SND responses to acute and sustained hypothermia.
Kenney
M J
MJ
Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas 66506, USA. Kenny@vet.ksu.edu
Blecha
F
F
Morgan
D A
DA
Fels
R J
RJ
D000208:Acute Disease; D002001:Adipose Tissue, Brown / Q000294:innervation*; D018686:Anesthetics, Intravenous; D000818:Animals; D002698:Chloralose; D007035:Hypothermia / Q000503:physiopathology*; D007375:Interleukin-1 / Q000494:pharmacology*; D007668:Kidney / Q000294:innervation*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013312:Stress, Physiological / Q000503:physiopathology; D013564:Sympathetic Nervous System / Q000187:drug effects*
D018686:Anesthetics, Intravenous; D007375:Interleukin-1; D002698:Chloralose