Many studies in animals have examined biochemical, immune andhistological changes during arthritis; however, the study of theeffects of arthritis on mobility has been largely neglected.Interleukin-1, administered by the intraarticular route into hamsterknee joints, resulted in inhibition of spontaneous wheel runningactivity; however, the effect was transient, lasting only throughthe evening following IL-1 administration. Here, IL1B is linked to arthritic joint disease.