Central infusion of interleukin-1 receptor antagonist fails to alter feeding and weight gain.
Interleukin-1 (IL-1) administered either i.p. or i.c.v. provokes sickness behaviors, including suppression of feeding. As well, the possibility exists that IL-1 contributes to the cascade of factors that regulate feeding under basal conditions. The current study assessed the contribution of IL-1 in the control of food intake and body weight under physiological conditions in male rats. Pretreatment with an IL- I receptor antagonist (IL-1ra, 16 mg/kg, i.p.) completely blocked the suppression of food intake produced by injection of IL-1beta (4 microg/kg, i.p.). However, neither daily injections of IL-1ra (16 mg/kg, i.p.) for 4 consecutive days nor infusion of IL-1ra (500 microg/day, i.c.v.) for 7 days altered daily food intake and the rate of body weight gain. These findings suggest while IL-1 may play a role in anorexia associated with sickness, this cytokine likely does not play a physiological role in the regulation of daily food intake and long-term energy balance.
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School of Psychology, University of Ottawa, Ontario, Canada.
Anisman
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Merali
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D000818:Animals; D004334:Drug Administration Schedule; D004435:Eating / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012795:Sialoglycoproteins / Q000494:pharmacology*; D015430:Weight Gain / Q000187:drug effects*
D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D012795:Sialoglycoproteins