Effects of thyrotropin releasing hormone (TRH) on glutamate-induced seizures in rats

We investigated effects of TRH on glutamate-induced seizures in rats. Rats were injected intraperitoneally with sodium glutamate in a dose (22.3 mmole/kg) equivalent to ED95 for generalized convulsions. Twenty five min later TRH in a dose of maximum effect (40 micrograms in the tartrate form) was injected intracerebroventricularly in order that the time of peak effect was simultaneous with the onset of seizure which was anticipated from the preliminary study. TRH delayed the onset of initial seizures significantly, though neither occurrence nor incidence of various seizure activities was affected. A trend of delay in the mean time of death was also observed. These results suggest that TRH has an inhibitory action against glutamate-induced seizures in rats, albeit mild.