Differential effects of IL-1ra on sickness behavior and weight loss induced by IL-1 in rats.
Peripheral and central injections of recombinant human interleukin-1 beta (IL-1 beta) have been shown to decrease social exploration and to induce body weight loss in rats. To characterize the receptor mechanisms of these effects, we used as a tool a specific antagonist of the receptors of IL-1, IL-1ra. Intraperitoneal (i.p.) administration of IL-1ra (8 mg/kg) blocked the effect of i.p. injection of IL-1 beta (4 micrograms/rat) on social behaviour but not on body weight. Central administration of IL-1ra (60 micrograms/rat, i.c.v.) abrogated the effects of centrally administered IL-1 beta (30 ng/rat, i.c.v.) on both social behaviour and body weight. Central injection of IL-1ra (4 micrograms/rat, i.c.v.) also attenuated the effects of i.p. administered IL-1 beta (4 micrograms/rat) on social behaviour but not on body weight. These results suggest that the effects of IL-1 beta on social behavior are mediated centrally and that its effect on the loss of body weight involves different receptor mechanisms.
Bluthé
R M
RM
INRA-INSERM U394, Domaine de Carreire, Bordeaux, France.
Beaudu
C
C
Kelley
K W
KW
Dantzer
R
R
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001831:Body Temperature / Q000187:drug effects; D005106:Exploratory Behavior / Q000187:drug effects; D006801:Humans; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D007375:Interleukin-1 / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D018123:Receptors, Interleukin / Q000037:antagonists & inhibitors; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000494:pharmacology; D012919:Social Behavior; D015431:Weight Loss / Q000187:drug effects*
D007375:Interleukin-1; D018123:Receptors, Interleukin; D011994:Recombinant Proteins