The Role of Dopamine D2-Like Receptors in the Occurrence of LFS Effects on Spontaneous Synaptic Currents

low-frequency electrical stimulation (LFS) has been considered as a new treatment method for epilepsy patients resistant to drug treatment, but its mechanism of action is not fully understood. Gi protein-coupled receptors such as dopamine D2-like receptors may play a role in mediating the effects of LFS. In this study, the role of dopamine D2-like receptors in the effects of LFS on seizure-induced spontaneous synaptic activity in the hippocampal CA1 region of fully kindled rats has been investigated. Animals were kindled by semi-rapid kindling method (6 stimulations per day) by electrical stimulation of the hippocampal CA1 region. In LFS-treated groups, animals received 4 LFS packets at 5 minutes, 6 hours, 24 hours, and 30 hours after the last LFS stimulation.Each LFS package consisted of 4 series with an interval of 5 minutes, and each series consisted of 200 pulses, and the pulse duration was 0.1 ms with a frequency of 1 Hz. Haloperidol (D2 receptor antagonist, mµ2) or bromocriptine (D2 receptor agonist, g/µlitµ2) was injected into the lateral ventricle immediately after the last kindling stimulation, before applying LFS. The obtained results showed that the application of LFS in kindled animals did not affect the spontaneous excitatory currents in the hippocampus, but it caused a decrease in the spontaneous inhibitory currents in the hippocampus. D2 receptor agonist did not mimic the effects of LFS. The use of haloperidol did not affect the effects of LFS. Therefore, spontaneous excitatory and inhibitory potentials are not a suitable quantity to investigate the effectiveness of LFS.