褪黑素对大鼠海马神经元谷氨酸所致毒性的拮抗作用

ANTAGONISTIC EFFECTS OF MELATONIN ON GLUTAMATE INDUCED NEUROTOXICITY IN RAT HIPPOCAMPAL NEURONS

在大鼠海马脑片上电刺激Ｓｃｈａｆｆｅｒ 侧支纤维， 胞外记录ＣＡ１ 区锥体细胞层诱发群体锋电位（ｐｏｐｕｌａｔｉｏｎ ｓｐｉｋｅ，ＰＳ） ， 观察灌流谷氨酸（Ｇｌｕ） 和褪黑素（ＭＥＬ） 对ＰＳ的影响。结果显示：５－０ ｍｍｏｌ／Ｌ浓度的Ｇｌｕ 可使ＰＳ值下降至对照值的４－１ ％ ； ＭＥＬ（０－４ 、０－５ 和０－６ μｍｏｌ／Ｌ） 与５－０ ｍｍｏｌ／ＬＧｌｕ 混合给药，ＰＳ值分别变化为对照值的１４－７ ％ 、１０５－２％ 、２４－３ ％ ； ＭＥＬ（０－５ μｍｏｌ／Ｌ） 、Ｇｌｕ （５－０ ｍｍｏｌ／Ｌ） ， 与赛庚啶（ＣＤＰ，０－５ μｍｏｌ／Ｌ） 混合给药，ＰＳ值下降至０ 。上述结果提示，５－０ ｍｍｏｌ／Ｌ浓度的Ｇｌｕ 有神经毒性作用， 但可为ＭＥＬ拮抗， 这可能由５ＨＴ受体所介导。

The effects of glutamate (Glu) and melatonin (MEL) on the evoked populaion spike (PS) following stimulation of the schaffer collateral fiber were studied by extracellular recording technique in perfused slices of rat hippocampus: 5 0 mmol/L Glu decreased the PS peak values to 4 1% of control. This effect of Glu (5 0 mmol/L) on PS peak values was changed to 14 7%, 105 2% and 24 3% of control by 0 4, 0 5, 0 6 μmol/L of MEL. But when the interaction between MEL (0 5 μmol/L) and Glu (5 0 mmol/L) was entirely suppressed by CDP (0 5 μmol/L), the PS values reduced to zero. These results suggest that the inhibitory action of MEL on Glu induced neurotoxicity may be mediated by 5 HT receptors.