Interleukin-8 modulates feeding by direct action in the central nervous system.
Interleukin-8 (IL-8) is released in response to infection, inflammation, and trauma. The most important stimuli for IL-8 release during these pathological processes are IL-1, tumor necrosis factor, and bacterial lipopolysaccharide (endotoxin), factors that have been shown to suppress feeding. In the present study, the participation of IL-8 on the central regulation of feeding was investigated. Intracerebroventricular (icv) microinfusion of recombinant human IL-8 (rhIL-8, 1.0-100 ng/rat) suppressed the short-term (2-h) food intake. The most effective dose of rhIL-8, 20 ng, decreased 2-h food intake by 25% and nighttime food intake by 23%. Intracerebroventricular microinfusion of anti-rhIL-8 antibody (200 and 500 ng) blocked the effect of 20 ng rhIL-8 on 2-h and nighttime food intakes. Computerized analysis of behavioral patterns for the 2-h period demonstrated a specific reduction of meal size (by 33%), whereas meal frequency and meal duration were not affected after the icv microinfusion of 20 ng rhIL-8. This short-term food intake suppression by icv rhIL-8 was accompanied by a small, but significant, increase in cerebrospinal fluid-brain and rectal temperatures. Intraperitoneal administration of rhIL-8 in doses equivalent to those administered centrally had no effect on food intake. The results suggest that IL-8 acts directly in the central nervous system to decrease feeding. This effect of IL-8 may contribute to the food intake suppression frequently accompanying pathological processes.
Plata-Salamán
C R
CR
School of Life and Health Sciences, University of Delaware, Newark 19716.
Borkoski
J P
JP
D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D002555:Cerebrospinal Fluid / Q000187:drug effects; D002940:Circadian Rhythm; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects*; D005247:Feeding Behavior / Q000187:drug effects; D007276:Injections, Intraventricular; D016209:Interleukin-8 / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins
D016209:Interleukin-8; D011994:Recombinant Proteins