A BEHAVIORALLY ACTIVE DOSE OF LIPOPOLYSACCHARIDE INCREASES SENSORY NEUROPEPTIDES LEVELS IN MOUSE SPINAL-CORD

To assess whether peripheral immune stimuli activate sensory afferents at behaviorally active doses, we measured the effects of lipopolysacc haride (LPS) on the levels of sensory neuropeptides in the spinal cord . LPS (10 mu g/mouse i.p.) increased the levels of substance P, neurok inin A, and calcitonin gene-related peptide in the spinal cord, the ma ximum being observed 1 hr post-injection. Pretreatment with indomethac in at a dose (5 mg/kg i.p.) which completely blocked the decrease in f ood-motivated behavior induced by LPS abrogated this effect.