Effects Of Remifentanil Of T Lymphocyte Proliferation And Natural Killer Cell Activity In Rats With Constriction Injury

We investigated the effects of acute and of chronic Remifentanil treatment on T-lymphocyte function and natural killer (NK) cell activity in rats receiving chronic constriction injury (CCI) of the sciatic nerve. T-Lymphocyte function was evaluated based on concanavalin-A (ConA) -induced splenocyte proliferation. The effects of Remifentanil on hyperalgesia were also assessed by measuring paw withdrawal thresholds (PWT) in rats. All of the rats that received CCI developed hyperalgesia while sham-operated rats did not. Hyperalgesia was dose-dependently reversed after acute (single injection) and after chronic (daily injection for 7 days) administration of Remifentanil but persisted in saline-treated CCI rats. There was no significant difference between sham and saline-treated CCI groups in splenocyte proliferation and NK cell activity. NK cell activity and splenocyte proliferation induced by ConA were significantly suppressed by acute Remifentanil treatment in a dose-dependent manner. The reversal of the hyperalgesia persisted throughout the period of chronic Remifentanil treatment. No tolerance to the suppression of NK cell activity and splenocyte proliferation was observed after chronic Remifentanil treatment. These data suggest that both acute and chronic Remifentanil treatment can cause a dosedependent reversal of hyperalgesia and inhibition of NK cell...