Protective Effects of Tetramethylpyrazine on Glutamate-Induced Neurotoxicity in Mice

The aim of this study was to investigate the potential protective effect of tetramethylpyrazine (TMP), one of available blood-activating and stasis-eliminating components from traditional Chinese medicines, on glutamate-induced neurotoxicity in mice and its possible mechanism. Mice, except for controls, received simultaneously intragastric (ig) administration of monosodium glutamate [MSG, 4.0 g/(kg·d)] or/and intraperitoneal (ip) administration of TMP [10, 20, 40 mg/(kg·d)] for 10 d, and then behavioral tests, as well as histopathological and immunohistochemical examination of hippocampi were performed to analyze the glutamate-induced functional and morphological changes and the possible protective effect of TMP. The results showed that ip administration of TMP countered the effects of ig administration of MSG on behavior and histopathology, suggesting that TMP was a neuroprotective agent. This study provides evidence that TMP possesses obviously neuroprotection against glutamate-induced neurotoxicity, and the neuroprotection effect may result from its inhibiting expression of NMDARs, consequently blocking-up Ca2+ influx through the receptor’s associated ion channel, which can be neurotoxic.