A. Montkowski et al., CENTRAL ADMINISTRATION OF IL-1 REDUCES ANXIETY AND INDUCES SICKNESS BEHAVIOR IN RATS, Pharmacology, biochemistry and behavior, 58(2), 1997, pp. 329-336
In the present study, we examined the effects of various doses of reco
mbinant human interleukin-1 beta on anxiety-like behaviour, on body te
mperature, and on behavioural changes typical of sick animals. First,
we assessed the behaviour of rats in the elevated plus-maze before and
20 min after intracerebroventricular injection of IL-1 at six doses r
anging from 0.001 to 100 ng. After treatment with 0.1 and 100 ng IL-1,
animals exhibited different anxiety levels. The dose effect on behavi
oural performance in the plus-maze appears to be nonlinear (parabolic
function), with the highest effects near a 0.1-ng dose and the lowest
near doses of 0.0 and 100 ng. In a second set of experiments, we exami
ned the effects of doses of 0.1 and 100 ng IL-1 (which had the most pr
onounced effects on performance in the plus-maze) on physical paramete
rs over a 24-h period. Using radiotelemetry we measured body temperatu
re, locomotor activity, food intake, and water consumption: a) in anim
als kept under basal resting conditions, and b) in animals exposed to
a novel environment prior to administration of IL-1. Both doses evoked
a fever response and reduced locomotor activity, but the increase in
body temperature did not correlate with the decrease in locomotor acti
vity and both effects did not occur at the time of behavioural testing
. Taken together, our data indicate that central administration of IL-
1 has anxiolytic-like properties. (C) 1997 Elsevier Science Inc.