Calmodulin Inhibitor Trifluoperazine Against Cerebral Ischemia And Mechanisms

Ischemic stroke is a leading cause of death and serious, long-term disability in adults. Until recently, modem medicine has had very little power over this disease, but the world of stroke medicine is changing and new and better therapies are being developed every day. Researchers are studying the mechanisms of this disease and ways to prevent this injury to the brain. Scientists hope to develop surgical techniques and neuroprotective agents to prevent this damage and restore important functions to the stroke patients. This paper studied the neuroprotective effects and mechanisms of Calmodulin antagonist using animal ischemia model in vitro.In this study, the effect of oxygen-glucose deprivation (OGD) on the intracelluar Ca2* and production of NO was investigated in cultured hippocampal neurons. The generation of NO and changes in intracellular Ca2* were evaluated using confocal laser scanning microscopy with diaminofluorescein diacetate (DAF-2 DA), an NO probe, and Fluo-3, a Ca2+ probe respectively. Results showed that OGD induced an increase in NO production and intracellular Ca2+ concentration ([Ca2+]j). when the extracellular calcium was removed, the increase in intercellular Ca2* during OGD was significantly lower, which suggested that ischemic increase in Ca2+ was mainly due to influx through plasma membrane Ca2+ channels. Calmodulin (CaM) antagonist trifluoperazine (TFP) could significantly reduced the OGD-induced elevation of [Ca2+]j .The increase in NO production was also attenuated by TFP dose-dependently. For calcium influx into cells through NMDA receptor was probably played an important pathogenetic role in ischemia, we studied the effect of TFP to Glu-induced The result showed that TFP reduced the increase of [Ca2+]j induced by Glu, which also indicated that TFP may inhibit Ca2+ influx during OGD by blocking NMDA receptor.We studied the effect of TFP on the changes of level of amino acids (Asp, Glu, Tau, GABA) in the culture medium of brain slices during OGD. It was found that OGD increase the release of amino acids and TFP can significantly inhibit the increase of the excitatory amino acids (EAA).3The protective effects of TFP against hypoxic brain injury were studied by the extracellular recording technique in rat hippocampal slices. The results showed that treated with TFP, the appearance of hypoxic injury potential (HIP) was lower and the recovery amplitude of PS after reoxygenation was significantly higher than that of OGD group. We also investigated the effects of TFP to survival activities of cultured neuron injured by OGD using WST-1 assay. It was found that optical density (OD) of TFP group is higher than that of OGD group. Therefore, the above results showed that TFP had protective effects against brain hypoxic injury.The protective effects and mechanisms of TFP in ischemia were studied in this thesis. The results indicated TFP have anti-ischemia effects through inhibiting EAA release, Ca2"1" overload and production of NO. Our experiments and results would be helpful for further studies in pathological mechanisms and clinic therapies to this disease.