Inflammatory and antiinflammatory effects of antidromic stimulation of dorsal roots in the rat.

Unilateral antidromic stimulation of the rat's lumbar dorsal roots evoked plasma extravasation in the skin of the corresponding hindpaw. Identical antidromic stimulation of the contralateral dorsal roots 4-5 minutes prior to the stimulation inhibited this response by 49%. No inhibition occurred when time interval between the stimulations was 60 minutes. It is concluded that not only inflammatory, but antiinflammatory mediators are released in response to activation of the peripheral endings of primary afferent neurons.