High-frequency repetitive transcranial magnetic stimulation does not change GABAA receptor-mediated inhibition in the rat hippocampus

We determined the effect of high-frequency (30 Hz) repetitive transcranial magnetic stimulation (rTMS) on γ-aminobutyric acid (GABA)A receptor-mediated inhibition in the rat hippocampus. Wistar rats had received rTMS treatment (1500 pulses/day, stimulus intensity of 2 folds of motor threshold) of the frontal brain for 7 consecutive days. The paired-pulse ratio (PPR) of population spike and field excitatory postsynaptic potential (fEPSP) in the hippocampal slices (CA1 area) and GABAA receptor α1 subunit mRNA expression levels in the hippocampus were analyzed. Repetitive TMS had no effects on paired-pulse ratio, fEPSP, and GABAA receptor α1 subunit mRNA expressions in the hippocampus. Our results suggest that high-frequency rTMS will induce cerebral excitation without any changes on GABAA receptor-mediated inhibition in the hippocampus.