胞外无钙时电刺激诱发海马脑片释放去甲肾上腺素  

ELECTRICAL STIMULATION EVOKES [~3H]NORADRENALINE RELEASE FROM HIPPOCAMPAL SLICES IN THE ABSENCE OF EXTRACELLULAR Ca^(2+)

作　　者：黄华玉[1] 

机构地区：[1]中国科学院上海生理研究所

出　　处：《神经科学》1995年第1期1-6,共6页Chinese Journal of Neuroscience

摘　　要：大鼠海马脑片用［３Ｈ］去甲肾上腺素（［３Ｈ］ＮＡ）孵育后，用无钙含２ｍｍｏｌ／ＬＥＧＴＡ任氏液灌流，用电刺激或高Ｋ＋诱发［３Ｈ］ＮＡ释放。电刺激诱发的［３Ｈ］ＮＡ释放被ＴＴＸ有力地抑制，被ＢＡＰＴＡ—ＡＭ显著地减弱，但ＴＴＸ和ＢＡＰＴＡ—ＡＭ对高Ｋ＋诱发的［３Ｈ］ＮＡ释放无作用。电刺激和高Ｋ＋诱发的［３Ｈ］ＮＡ释放均被蛋白激酶Ｃ（ＰＫＣ）的激活剂佛波醇脂加强，并被α２－自身受体激动剂ｃｌｏｎｉｄｉｎｅ所削弱。结果提示：在胞外无钙时，电刺激诱发海马脑片释放［３Ｈ］ＮＡ是来自囊泡的胞吐；Ｎａ＋进入神经末梢和内Ｃａ２＋释放参与这一诱发释放过程，但不参与高Ｋ＋诱发［３Ｈ］ＮＡ释放机制。The hippocampal slices preincubated with [3H]noradrenaline ([3H]NA) were superfused with Ca2+ -free medium containing 2 mmol/L EGTA and stimulated by electrical field stimulation or high K+. The electrically evoked [3H]NA release was inhibited potently by TTX and significantly by Ca2+ chelator, tetraacetoxy methyl ester of 1-2-bis - (2 -aminopenoxy) ethane -N, N, N', N' tetraacetic acid (BAPTA -AM), whereas TTX and BAPTA-AM had no effect on K+-evoked [3H]NA release. Both the evoked [3H]NA release were enhanced by the activator of protein kinase C, 4β-phorbol 12,13 -dibutyrate and diminished by the agonist of α2 -autoreceptor, clonidine. The findings suggest that under extracellular Ca2+-free conditions electrical stimulation of hippocampal slices evokes exocytotic release of [3H]NA and that Na+ entry and the liberation of internal Ca2+ stores are involved in the release process, but not in that induced by high K+.

关 键 词：电刺激 海马 去甲肾上腺素 钙 蛋白激酶C 高钾 

分 类 号：Q426[生物学—神经生物学]