Abstracts

Rationale: Transcranial electrical stimulation (TES) applied from concentric ring electrodes has emerged as a possible alternative therapy for cognitive and neuropsychiatric diseases. Transcranial focal stimulation (TFS) is an alternating current stimulation TES technique with a wide therapeutic potential. We have found that TFS potentiates anti-seizure drugs (Besio et al. 2013), delays kindling (Valdes-Cruz et al. 2019), reduces extracellular glutamate and increases GABA (Santana-Gomez et al. 2015), and does not affect memory (Rogel-Salazar et al. 2013). Nevertheless, the biological mechanisms behind the TFS effects are unknown. The present study aimed to investigate the gene expression profile of the cerebral cortex and hippocampus after a short course of TFS in normal brain.

Methods: Rats were habituated for manipulation for one week. One day after the last manipulation, rats received TFS. The TFS consisted of the application of alternating current through the TCRE and Ten20 paste on the shaved head of the rats. The TFS parameters were: square biphasic pulses of 200 µs, at a frequency of 300 Hz, with an intensity of 50 mA, for 5 minutes. Animals were killed by decapitation 3.5 h after TFS and the cerebral cortex and hippocampus were dissected and frozen and used for microarray analysis. The results were compared to those obtained from sham-stimulated rats (n=5), not receiving any TFS current. Relevant target genes were selected based on their biological processes, molecular function, and cellular localization. Relevant target genes were further normalized to visualize differential gene expression among experimental groups.

Results: The cerebral cortex samples formed a clear differential expression profile. A total of differentially expressed genes of 102 in the cerebral cortex and 2 in the hippocampus were found. Of the 102 differentially expressed genes four genes were chosen due of their high or low expression as their function. TFS increased the expression of Nsf (120%, p = 0.0004) and decreased the expression of Sema3b (57.6%, p = 0.0004) in the cerebral cortex. While in the hippocampus, TFS increased the expression of Acsm5 (200%, p = 0.001) and Cml3 (208%, p = 0.001).

Conclusions: A short course applying TFS for 5-minutes modifies the gene expression profile of the brain._x000D_ The effects were more pronounced in the cerebral cortex rather than in the hippocampus. Understanding the effects produced by TFS may improve the future potential use of this technique as a clinical tool in the treatment of epilepsy.

References: _x000D_ Besio et al. TFS potentiates diazepam. Epilepsy Behav. 2013;28:432-436._x000D_ Valdés-Cruz A, et al. TFS antiepileptogenic effects. Experimental Neurology. 2019._x000D_ Santana-Gómez, et al. TFS reduces the convulsive. Epilepsy Behav. 2015;49:33-39._x000D_ Rogel-Salazar et al. Transcranial focal electrical stimulation Epilepsy Behav. 2013;27:154-158._x000D_
Funding: National Council of Science and Technology of Mexico (CONACYT, scholarship No. 622940 to DPP)