title: Peripheral nerve stimulation suppression of C-fiber-evoked flexion reflex in rats. Part 1: Parameters of continuous stimulation.
abstract: Transcutaneous electrical nerve stimulation (TENS) is now a well established clinical technique to alleviate chronic pain. Its mechanism of action remains unknown and the stimulation parameters used are based on subjective reports from patients. In the present study, a systematic investigation has been performed with conditioning stimulation of different parameters delivered to a dissected skin nerve in the lightly anesthetized rat, utilizing the size of a C-fiber-evoked flexion reflex as a measure of transmission from nociceptive afferent fibers in the spinal cord. A stimulation intensity that recruited both A-beta and A-delta fibers was more effective in depressing the C-fiber-evoked reflex at all frequencies studied than were intensities activating A-beta fibers only. A stimulation frequency of 80 Hz gave the most profound inhibition. The implications for clinical treatment are discussed.
mesh_terms: D000818:Animals; D003213:Conditioning, Psychological / Q000502:physiology; D004599:Electric Stimulation Therapy; D010525:Peripheral Nerves / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012018:Reflex; D012867:Skin / Q000294:innervation; D013127:Spinal Nerves / Q000502:physiology; D004561:Transcutaneous Electric Nerve Stimulation