Low-frequency Electrical Stimulation of the Hippocampus Plays a Role in the Treatment of Pharmacoresistant Epilepsy by Blocking the PKA-CREB Pathway

Abstract

Objective: The objective of this study is to study the mechanism of Low frequency electrical stimulation (LFS) in the treatment of drug-resistant epilepsy by regulating the protein kinase A (PKA)-cAMP response element-binding protein (CREB) signaling pathway upstream of gamma aminobutyric acid A (GABAA) receptor. Methods: Primary hippocampal neurons were extracted and cultured from fetal rat brains and randomly divided into the normal control group, PKA-CREB agonist group, and PKA-CREB inhibitor group. Drug-resistant epileptic rats were established and randomly divided into the pharmacoresistant group, LFS group, PKA-CREB agonist combined with hippocampal LFS group, and PKA-CREB inhibitor combined with hippocampal LFS group. The normal rats were in the normal control group and drug-sensitive rats were in the pharmacosensitive group. The seizure frequency of epileptic rats was determined using video surveillance. The expression of PKA, CREB, p-CREB, and GABAA receptor subunits α1 and β2 of each group were detected using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting assays. Results: The in vitro expression levels of PKA, CREB, and p-CREB in the agonist group were significantly higher than those in the normal control group (NRC group), while the expression levels of GABAA receptor subunits α1 and β2 were significantly lower than those in the NRC group. The expression levels of PKA, CREB, and p-CREB in the inhibitor group were significantly lower, while the expression levels of GABAA receptor subunits α1 and β2 were significantly higher than those in the NRC group. The in vivo seizure frequency was significantly lower in the LFS group than in the pharmacoresistant group (PRE group). Compared to the LFS group, the seizure frequency and the expression levels of PKA, CREB, and p-CREB in the rat hippocampus were significantly higher, and the expression levels of GABAA receptor subunits α1 and β2 were significantly lower in the agonist group. The results in the inhibitor group were exactly the opposite of those in the agonist group. Conclusion: The PKA-CREB signaling pathway is involved in the regulation of GABAA receptor subunits α1 and β2. In addition, LFS plays an important role in increasing GABAA receptor expression by regulating the PKA-CREB signaling pathway.