The effects of pretreatment with low-frequency transcranial magnetic stimulation on rats with pilocarpine-induced seizures

Abstract

Objective To study the effects of low-frequency transcranial magnetic stimulation (TMS) on rats with seizures induced by lithium-pilocarpine. Methods Rats were randomly divided into five groups and pre-treated with TMS at 75% of the stimulator's maximum output, but at 0 Hz (the sham group), 0.3 Hz, 0.5 Hz, 0.8 Hz and 1.0 Hz, respectively. After stimulation every day for 2 weeks, a model of acute epilepsy was induced u-sing iithium-pilocarpine. Subsequent behavior and the latencies of seizures were observed, and the severity of the sei- zures was quantitatively evaluated for 90 rain. Results The seizure latencies were significantly prolonged in all the other groups relative to the sham group (P<0.05). The prolongation in the 0.5 Hz and 0.8 Hz groups was signifi-cantly greater than in the 0.3 Hz and 1.0 Hz groups. The severity of seizures in the 0.3 Hz and 1.0 Hz groups was not significantly different from that in the sham group, but most of the rats in the 0.5 Hz group and the 0.8 Hz group experienced much lighter seizures, with seizure severity scores significantly lower than those in the other 3 groups. Conclusions Pretreatment with TMS at 0.3 to 1.0 Hz led to a longer latency of seizure onset. 0.5 Hz and 0.8 Hz gave the longest latencies and showed conspicuous antiepileptie effects. Key words: Transcranial magnetic stimulation ; Epilepsy; Latency; Epileptic seizures; Lithium-pilo-carpine