Anxiolytic-like effects of extremely low frequency electric field in stressed rats: involvement of 5-HT2C receptors

Abstract

Background

Possible modulatory effects of noninvasive brain stimulation have gained interest recently. In our study, the effect of low frequency electric fields (LF-EF) on stress-induced electrophysiological, behavioral changes and the possible involvement of serotonergic 5-HT2C receptors were investigated.

Materials and methods

A total of eight groups including the control groups were formed by applying LF-EF with or without a 5-HT2C receptor agonist to naïve or acute stress exposed rats to demonstrate the effects of LF-EF. LF-EF administration at 10 kV/m was started 30 min before acute stress application and lasted for 1 h in total. Anxiety levels and social interaction were evaluated using the elevated plus maze test and social interaction test, respectively. Auditory evoked potentials (AEP) were recorded by using ascending loudness paradigms. Loudness dependence AEP (LDAEP) was calculated by using amplitude values to analyze serotonergic transmission. Serotonin and glucocorticoid levels were measured in the frontal cortex and hippocampus.

Results

It was observed that the applied LF-EF reduced the anxiety behavior, and attenuated the LDAEP responses in stress and/or 5-HT2C receptor agonist applied groups. In parallel, an increase in serotonin levels and a decrease in glucocorticoid levels were observed. However, LF-EF exposure was ineffective in impaired social interaction.

Conclusions

Our findings show that 10 kV/m LF-EF administration may modulate the neural network and physiological responses associated with mild acute stress. 5-HT2C receptor dependent functions are thought to play a role in the anxiolytic effect of LF-EF.

Keywords:

• Stress
• low frequency electric field
• serotonin
• auditory evoked potentials
• anxiety
• social interaction

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Additional information

Funding

This study was supported by a grant from Akdeniz University Research Foundation, Turkey [Grant No: TSA-2018-3651].

Notes on contributors

Deniz Kantar

Deniz Kantar received her PhD degree from Akdeniz University, Turkey, in 2016. She is a postdoctoral researcher at Department of Biophysics, Akdeniz University. Her research interests include biological effects of electromagnetic fields, neurodegenerative disease, electrophysiology, behavioural and cognitive neuroscience.

Alev Duygu Acun

Alev Duygu Acun is a PhD student in Akdeniz University. She is a researcher at Department of Biophysics, Akdeniz University. Her areas of interest are biological and molecular effects of electromagnetic fields, neurodegenerative diseases, electrophysiology, behavioral and cognitive science.

Hakan Er

Hakan Er received his PhD degree from Akdeniz University, Turkey, in 2018. He is Assistant Professor in Vocational School of Health Services of Akdeniz University. His main research fields are biological effects of electromagnetic fields, neurodegenerative disease and electrophysiology.

Ebru Afsar

Ebru Afsar received her Phd degree from Akdeniz University, Turkey, in 2021. She is a lecturer at Department of Nutrition and Dietetics, Kültür University. Her research include biological effects of nutritions on metabolism and neurodegenerative disease.

Piraye Yargıcoglu

Piraye Yargıcoglu received her PhD degree from Akdeniz University, Turkey, in 1984. She is is the founder of Biophysics Department at Akdeniz University. Her main research interests include epilepsy, neurodegenerative disease and electrophysiology.