Transcranial direct current stimulation (tDCS) prevents chronic stress-induced hyperalgesia in rats.

BACKGROUND: Chronic stress (CS) is associated with a decrease in pain threshold caused by the changes in neural pain circuits. It can be associated to glucocorticoid imbalance with alterations in neural circuitry. Inhibition of stress-induced pain-related neural changes by using techniques that safely induce neuroplasticity such as transcranial direct current stimulation (tDCS) may prevent hyperalgesia triggered by CS.

OBJECTIVE: This study aimed to verify the effect of tDCS performed prior to CS exposure on nociceptive response.

METHODS: Thirty-two rats were distributed in the following groups: control; stress; sham-tDCS + stress; and tDCS + stress. Bicephalic active tDCS was performed for 8 consecutive days before the CS exposure. The pain threshold was evaluated using a hot plate and tail flick latency (TFL) tests.

RESULTS: The tDCS exposure increased the pain threshold on stressed rats.

CONCLUSION: The data obtained indicate that the treatment with bicephalic active tDCS before chronic stress exposure prevents stress-induced hyperalgesia.