Interaction of bradykinin with substance P on vascular permeability and pain response.

Combination of bradykinin with substance P exerted synergistic effects on vascular permeability and pain response in mouse paw. Denervation of sciatic nerve reduced significantly bradykinin-induced vascular permeability, suggesting the involvement of sensory nerves. The bradykinin-induced vascular permeability was also reduced by intravenous injection of a substance P-antagonist. The results suggest that neuronal substance P takes part in the action of bradykinin on inflammation and pain sensation.