Abstract: AIM: To study the protection of iptakalim hydrochloride (Ipt) against brain anoxia in mice.METHODS: The models of brain anoxia were made in mice after the administration of Ipt (0.5, 2.0, 8.0 mg·kg^-1, n =12, ig) for 3 wk.NS and vitamin E were set as controls.The glutathione proxidase (GSH-PX) activity, superoxide dismutase (SOD) activity and the lipid peroxide (MDA) content were determined in the brain homogenates of models, and the values of erythrocyte membrane fluidity were measured by the fluorescence polarization technique with DPH fluorescence probe.RESULTS: Compared with the control groups, Ipt (0.5, 2.0, and 8.0 mg·kg^-1, ig) markedly prolonged the breathing time and increased the fluidity of erythrocyte membrane in a dwse-dependent manner, but had no apparent effects on the activity of GSH-PX and SOD.CONCLUSION: The protection of Ipt against brain anoxia is related to increasing the fluidity of erythrocyte membrane and decreasing blood viscosity.

Key words: iptakalim hydrochloride, brain anoxia, erythrocyte membrane fluidity, blood viscosity, MDA, SOD, GSH-PX