Article

The objective of this study was to investigate the effect of high-frequency
transcutaneous electrical nerve stimulation (HF-TENS) in antihyperalgesia,
assessed through changes of sciatic nerve activity and its effects on
cardiorespiratory parameters, using formalin-induced nociception in anesthetized
rats. The animals were divided into formalin (FORM) and HF-TENS groups. All rats
received injections of 5% formalin (50 mul, right hind-paw). The sciatic nerve
activity and cardiopulmonary parameters (mean arterial pressure, heart rate, and
respiratory frequency) were measured, and then the serum levels of serotonin
(5-HT) were determined by an enzyme-linked immunosorbent assay kit. The formalin
injection was able to increase the sciatic nerve activity, heart rate, and
respiratory frequency. The treatment with HF-TENS significantly reduced the
sciatic nerve activity and respiratory frequency 20 minutes after formalin
injection and was able to increase serum 5-HT. Furthermore, when comparing the
groups, reductions in the mean arterial pressure, heart rate, respiratory
frequency, and sciatic nerve activity were shown at different times. Thus, we
concluded that HF-TENS was capable of inducing analgesia, which was most likely
related to increased serotonin release. Moreover, we demonstrated that TENS was
able to block the adverse cardiovascular and respiratory changes induced by pain.
Further neurophysiological studies are necessary to clarify the intrinsic
mechanisms underlying HF-TENS-induced analgesia.

Langue : ANGLAIS