Repetitive transcranial magnetic stimulation (rTMS) increases the release of dopamine in the nucleus accumbens of morphine-sensitized rats during drug-withdrawal

The abstinence syndrome in drug-dependent subjects is associated with subjective symptomatology including anxiety, anhedonia, dysphoria, depression and drug craving. Recent studies in rats have shown that withdrawal from chronic drug abuse is associated with a significant dysregulation in dopamine (DA) release in mesolimbic structures, especially in the shell region of the nucleus accumbens.

In the present study rats were treated over a period of seven days with a morphine sensitization scale. Three days after the last morphine injection, acute rTMS was applied. In this microdialysis study, we provide first evidence that acute rTMS is able to increase dopamine concentration in the nucleus accumbens in both control animals and in morphine-sensitized rats during abstinence. The dopamine release in morphine-sensitized rats was significant higher than in controls. Therefore, rTMS might gain a potential therapeutic role in the treatment of dysphoric and anhedonic states during drug withdrawal in humans.