Influence of Coriaria Lactone on Ca2+-activated K+ channels in rat hippocampal pyramidal neurons / 中国组织工程研究

ABSTRACT

BACKGROUND: Electrical activity of nerve cells is based on the ion channel activity on cell membrane. Epilepsy is basically characterized by abnormal neuronal discharge. The foundation is ion channel activation on cell membrane and ion transmembrane movement, however, whether Ca2+-activated K+ channel involves in epilepsy induced by Coriaria Lactone is still unclear.OBJECTIVE: Considering rat hippocampal pyramidal neurons as target,we investigate the effect of Coriaria Lactone on neuronal Ca2+-activated K+ channels in epilepsy induced by Coriaria Lactone.DESIGN: Randomized controlled experimental trials.SETTING: Department of Neurology, West China Hospital, Sichuan University and Institute. of Myocardium Electrophysiology of Luzhou Medical College.MATERIALS This experiment was carried out in Luzhou Medical College, Sichuan Province, from May to December 2000. Totally 100 Wistar infant rats within 24-hour ages were selected.METHODS: Wistar infant rats were anaesthetized and its hippocampus was obtained under disinfected state, pyramidal neurons were cultured for 7-10 days, neurons growing well with typical shape model were colleted normal control group, 19 dishes were added with DMEM culture medium,given different membrabe voltage and then followed by adding in te3 subgroups with 8 dishes each one. Added seperately DMEM culture medium containing f0-8, 10-7, 10~ mol/L concentration of calcium ion, and 2.0 mL/L Coriaria Lactone induced epilepsy group added with DMEM culture medium with different dosages of Coriaria Lactone and finally tetraethylamine in each concentration of 26 dishes for totally 130 dishes.Cell-attache method and inside-out method of patch-clamp technique were used to record the neuronal single channel electricity. The open probability, average opening hour and closing hour, electric current amplitude of channel were analyzed.activated K+ channels of pyramidal neurons at normal, various membrane To observe and record the influence of Coriaria Lactone on the activation of pyramidal neuronal cell membrane, as well as the role of tetraethylamine.were only small amount of pyramidal neurons randomly opening its Ca2+-activated K+ channels and it displayed obvious voltage-dependent property.The channel electric conductance was (122.79±21.68) pS. The channels the inside-out condition, Ca2+-activated K+ channel displayed calcium iondependent property. The average opening rate was 0.022±0.006, 0.040±0.007, 0.142±0.049 when the calcium concentration was 10-8, 10-7,aria Lactone could increase the opening rate of Ca2+-activated K+ channels when the free calcium ion in bath solution was 10-8 mol/L and memLactone, 1.0 mL/L Coriaria Lactone could increase the average opening time of Ca2+-activated K+ channels (1.867±0.210, 6.900±0.120, P ＜ 0.01), and reducing the average closing time (78.505±7.192,6.233±0.854, P ＜ 0.01).CONCLUSION: In epilepsy induced by Coriaria Lactone, the activation of Ca2+-activated K+ channels might play an important role of negative modulation.