[Intracerebroventricular injection of interleukin-2 inhibits splenic sympathetic nerve activity]

The effect of central administration of interleukin-2 (IL-2) on the splenic sympathetic nerve activity was studied. Intracerebro ventricular infusion of recombinant human IL-2 (300 U/rat) elicited marked long term (> 120 min) decrease in the electrical activity of the splenic nerve without altering blood pressure and body temperature. This splenic effect could be blocked by prior or post treatment with an opioid antagonist naloxone (1 mg/kg, iv). Naloxone alone injected intravenously had no effect on the splenic nerve activity. These results imply that the inhibitory effect of intracerebral IL-2 on splenic sympathetic nerve activity is mediated by opioid receptors.