Investigation of The Learning and Memory Enhancing Effects of 0.25 mA and 0.5 mA Anodal and Cathodal Transcranial Direct Current Stimulations in Healthy Rats

Abstract

Objective: Our aim in this study was to investigate the effects of tDCS, which is known to be effective on AM-PA and NMDA, with different anodal and cathodal stimulation types and 0.25 mA and 0.5 mA current intensi-ties on learning and memory by behavioral and molecular mechanisms. Methods: 50 male Wistar rats weighing 290-310 g were divided into 5 groups as control, C1-tDCS, C2-tDCS, A1-tDCS and A2-tDCS. In the C1-tDCS group, 0.25 mA cathodal tDCS stimulation for 30 min per day for 5 days, in the C2-tDCS group for 30 min per day for 0.5 mA cathodal tDCS stimulation for 5 days, in the A1-tDCS group for 5 days with 0.25 mA anodal tDCS stimulation for 30 min per day and A2-tDCS group The tDCS group received 0.5 mA anodal tDCS stimulation for 30 minutes per day for 5 days. On the 6th and 7th days of the experiment, the locomotor activity, learning and memory behaviors of the rats were evaluated by open field test, y maze test and object localization test. In addition, glutamate levels were measured in hippocampus tis-sues by ELISA method. Results: It was observed that there were non-significant decreases in the results of the C1-tDCS and C2-tDCS groups in which cathodal stimulation was applied compared to the control group in locomotor activity, learning and memory data. On the other hand, an increase was observed in the data of the A1-tDCS and A2-tDCS groups in which anodal stimulation was applied, and the increase in the data of the A2-tDCS group from these groups was found to be statistically significant compared to the control (p<0.05). Similar results were also seen in glu-tamate levels. A non-significant decrease in glutamate levels was observed in the C1-tDCS and C2-tDCS groups compared to the control, while an insignificant increase in glutamate levels in the A1-tDCS group was observed. On the other hand, there was a significant increase in glutamate level in the A1-tDCS group compared to the control group (p<0.05). Conclusion: In conclusion, our data showed that 0.5 mA anodal tDCS stimulation for 30 min for 5 days can enhance learning and memory on the glutamatergic pathway.