ABSTRACT
The purpose of the study was to investigate whether the small fiber-evoked dorsal root reflex (DRR) can be obtained by electrical stimulation of the peripheral nerve in rats. Fifty-one DRRs were recorded from different kinds of fiber filaments in the proximal ends of the cut L(5) dorsal root following electrical stimulation of the sural nerve. According to the kind of afferent fibers in the sural nerve associated with the DRRs from dorsal root, these DRRs were divided into five different types: A(alphabeta) fiber-evoked A(alphabeta).DRR (A(alphabeta)- A(alphabeta).DRR), A(betadelta) - A(delta ).DRR, A(betadelta)-C.DRR, A(alphabetadelta)-C.DRR and C-C.DRR. The results obtained show that the DRR can be obtained from either A-fibers (including A(delta )-fibers) or C-fibers of dorsal root filaments by stimulation of the sural nerve. It is therefore suggested that either A(delta ).DRR or C.DRR can be used as a validity index of presynaptic inhibition of the thin primary afferent terminals for investigation of the modulation mechanisms of peripheral effectors.