FURTHER SUBSTANTIATION OF A SIGNIFICANT ROLE FOR THE SYMPATHETIC NERVOUS-SYSTEM IN INFLAMMATION

This study provides significant new evidence substantiating a role of the postganglionic sympathetic neuron in plasma extravasation in the k nee-joint of the rat. Increased plasma extravasation produced by the p otent inflammatory mediator bradykinin was mimicked by 6-hydroxydopami ne, a selective stimulator of sympathetic fibers. Various treatments ( chemical sympathectomy, co-perfusion with the local anesthetic lidocai ne, or co-perfusion with depolarizing concentrations of potassium) sim ilarly modulated plasma extravasation induced by both bradykinin and 6 -hydroxydopamine, but not that produced by platelet activating factor. We also showed that bradykinin is able to release norepinephrine in t he knee-joint, indicating action on the sympathetic postganglionic neu ron. In summary, these experiments provide substantial additional evid ence supporting a significant contribution of the sympathetic post-gan glionic neuron terminal to inflammatory plasma extravasation.