TY - JOUR
T1 - Inhibition of primate spinothalamic tract cells by TENS
AU - Lee, K. H.
AU - Chung, J. M.
AU - Willis, W. D.
PY - 1985
Y1 - 1985
N2 - Transcutaneous electrical nerve stimulation (TENS) was applied in an experimental animal model to investigate the underlying mechanisms of this treatment. Recordings were made from identified spinothalamic tract (STT) neurons in the lumbosacral spinal cords of seven anesthetized monkeys. The STT cells were activated by stimulating the common peroneal nerve at a suprathreshold intensity for C-fibers. Evoked responses of C-fibers were compared before, during, and after application of TENS for 5 minutes from a commercially available TENS unit. The current delivered by the TENS unit was monitored. In 14 STT cells, some degree of inhibition of C-fiber evoked responses occurred only when the intensity of TENS exceeded the threshold of Aδ fibers. At a given stimulus intensity, bursts of pulses repeated at a low rate were more effective than high-rate pulses. When TENS was applied to an area of the skin within a cell's receptive field, it was more effective than when it was applied outside the receptive field. The C-fiber volley recorded from a peripheral nerve was not reduced in size, and there was no substantial changes in its latency due to TENS. The inhibition of the activity of STT cells was not altered appreciably after intravenous injection of naloxone hydrochloride. These results suggest that TENS produces central nervous system inhibition by activating Aδ afferent fibers. The inhibitory effects of TENS on STT cells appear to be due to a mechanism that does not involve release of endgenous opioid substances.
AB - Transcutaneous electrical nerve stimulation (TENS) was applied in an experimental animal model to investigate the underlying mechanisms of this treatment. Recordings were made from identified spinothalamic tract (STT) neurons in the lumbosacral spinal cords of seven anesthetized monkeys. The STT cells were activated by stimulating the common peroneal nerve at a suprathreshold intensity for C-fibers. Evoked responses of C-fibers were compared before, during, and after application of TENS for 5 minutes from a commercially available TENS unit. The current delivered by the TENS unit was monitored. In 14 STT cells, some degree of inhibition of C-fiber evoked responses occurred only when the intensity of TENS exceeded the threshold of Aδ fibers. At a given stimulus intensity, bursts of pulses repeated at a low rate were more effective than high-rate pulses. When TENS was applied to an area of the skin within a cell's receptive field, it was more effective than when it was applied outside the receptive field. The C-fiber volley recorded from a peripheral nerve was not reduced in size, and there was no substantial changes in its latency due to TENS. The inhibition of the activity of STT cells was not altered appreciably after intravenous injection of naloxone hydrochloride. These results suggest that TENS produces central nervous system inhibition by activating Aδ afferent fibers. The inhibitory effects of TENS on STT cells appear to be due to a mechanism that does not involve release of endgenous opioid substances.
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U2 - 10.3171/jns.1985.62.2.0276
DO - 10.3171/jns.1985.62.2.0276
M3 - Article
C2 - 3871474
AN - SCOPUS:0021999195
SN - 0022-3085
VL - 62
SP - 276
EP - 287
JO - Journal of neurosurgery
JF - Journal of neurosurgery
IS - 2
ER -