Transcranial direct-current stimulation increases extracellular dopamine levels in the rat striatum

Abstract

Background: Transcranial direct-current stimulation (tDCS) is a non-invasive procedure that achieves polarity-dependent modulation of neuronal membrane potentials. It has recently been used as a functional intervention technique for the treatment of psychiatric and neurological diseases; however, its neuronal mechanisms have not been fully investigated in vivo.Objective/Hypothesis: To investigate whether the application of cathodal or anodal tDCS affects extracellular dopamine and serotonin levels in the rat striatum.Methods: Stimulation and in vivo microdialysis were carried out under urethane anesthesia, and microdialysis probes were slowly inserted into the striatum. After the collection of baseline fractions in the rat striatum, cathodal or anodal tDCS was applied continuously for 10 min with a current intensity of 800 μA from an electrode placed on the skin of the scalp. Dialysis samples were collected every 10 min until at least 400 min after the onset of stimulation.Results: Following the application of cathodal, but not anodal, tDCS for 10 min, extracellular dopamine levels increased for more than 400 min in the striatum. There were no significant changes in extracellular serotonin levels.Conclusion: These findings suggest that tDCS has a direct and/or indirect effect on the dopaminergic system in the rat basal ganglia.

Transcranial direct current stimulation (tDCS) reverts behavioral alterations and brainstem BDNF level increase induced by neuropathic pain model: Long-lasting effect

“…The stimulation of dopaminergic neurons increases locomotor activity (Fishman et al, 1983), which proves the importance of these neurons to the modulation of this behavior. The use of tDCS in humans is known to increase the levels of extracellular dopamine (Tanaka et al, 2013). Arguably, then, tDCS treatment modulates the dopaminergic system in the frontal cortex, promoting dopamine release and consequently improving locomotor and exploratory activities of CCI rats.…”

Non-Invasive Brain Stimulation and its Supposed Site of Action in the Rehabilitation of Parkinson’s Disease and Stroke

“…The motor deficit of Parkinson's disease can be influenced by tDCS applied parallel over the motor and prefrontal area [20]. Similarly to the rTMS, one of the supposed sites of action of tDCS -according to animal studies -is the dopamine release in the striatum [21]. These promising results urge the involvement of non-invasive brain stimulation in the treatment of Parkinson's disease because the respond for dopaminergic therapy is less effective over years.…”

Effects of Successful Experience and Positive Feedback on Learning and Rehabilitation

“…Notably, Monti et al reported that cathodal tDCS of Wernicke's area, as opposed to anodal tDCS, enhanced the performance of aphasic patients in a picture-naming task [ 69 ]. In animal models, tDCS appears to infl uence motivation and reward systems [ 70 ] and thus has been suggested to alter preference and/or craving behaviors. Bilateral frontal cortical tDCS altered preference in patients with addictive disorders and reduce cravings for alcohol [ 71 ], smoking [ 72 ], and even for specifi c foods [ 73 ].…”