Abstract: AIM: To study the effects of midazolam on sodium channels of hippocampalPyramidal neurons,and to investigate mechanisms whereby midazolam mediates amnesia.METHODS: Sodium current was recorded by whole-cellPatch clamPtechnique in the acutely isolated neurons.Size of currents and steady activation curve were measured.RESULTS: Sodium channels were inhibited by midazolam in a reversibly manner.The sodiumPeak current was reduced by (7.95± 7.46)% and(25.37±8.31)%(P<0.01)at 0.1 and 10μmol·L^-1of midazolam,respectively.The steady activation curve shifted right significantly caused by 10μmol·L^-1midazolam.CONCLUSION: Midazolam inhibits sodium current slightly,suggesting that effects of midazolam on sodium channels are not the main mechanism in amnesia.

Key words: pharmacodynamics, midazolam, hippocampus, pyramidal neurons, sodium channels, patch clamp