Depressed immune function is well documented in protein calorie malnutrition (PCM). Also, central noradrenergic
hyperactivity has recently been reported in malnourished animals. Increase in central noradrenaline activity could be responsible
for cell-mediated immune depression. The present study is designed to address this hypothesis by testing whether neurotoxic
lesion of central noradrenergic systems by 6-hydroxydopamine (6-OHDA) could improve lymphoproliferative response to
mitogens and interleukin (IL)-1 production in PCM rats. A significant enhancement of lymphoproliferative response to
concanavalin A (ConA) and in IL-l production was observed in spleen mononuclear cells of PCM rats injected intracerebroventricularly
with 120 pg of 6-OHDA, as compared with solvent injected and untreated PCM animals. A significant decrease in
brain noradrenaline levels was produced in the drug-injected animals. These results suggest that central noradrenergic
hyperactivity is one of the mechanisms involved in the immunodepression produced by malnutrition.