Heemskerk F M, Schrama L H, Gianotti C, Spierenburg H, Versteeg D H, De Graan P N, Gispen W H
Division of Molecular Neurobiology, Rudolf Magnus Institute, University of Utrecht, The Netherlands.
J Neurochem. 1990 Mar;54(3):863-9. doi: 10.1111/j.1471-4159.1990.tb02331.x.
In situ phosphorylation of the presynaptic protein kinase C substrate B-50 was investigated in rat hippocampal slices incubated with the convulsant drug 4-aminopyridine (4-AP). Phosphorylation of B-50 was significantly enhanced 1 min after the addition of 4-AP (100 microM). This increase by 4-AP was concentration dependent (estimated EC50 30-50 microM). Concomitant with the changes in B-50 phosphorylation, 4-AP also dose-dependently stimulated [3H]noradrenaline [( 3H]NA) release from the slices. 4-AP stimulated [3H]NA release within 5 min to seven times the control level. The B-50 phosphorylation induced by 4-AP remained elevated after removal of the convulsant, this is contrast to B-50 phosphorylation induced by depolarization with K+. A similar persistent increase was observed for [3H]NA release after a 5-min incubation period with 4-AP. These results give more insight into the molecular mechanisms underlying 4-AP-induced epileptogenesis and provide further evidence for the correlation between B-50 phosphorylation and neurotransmitter release in the hippocampal slice.
在与惊厥药物4-氨基吡啶（4-AP）孵育的大鼠海马切片中，研究了突触前蛋白激酶C底物B-50的原位磷酸化。加入4-AP（100微摩尔）后1分钟，B-50的磷酸化显著增强。4-AP引起的这种增加呈浓度依赖性（估计EC50为30 - 50微摩尔）。与B-50磷酸化的变化同时，4-AP也剂量依赖性地刺激切片中[3H]去甲肾上腺素[（3H）NA]的释放。4-AP在5分钟内将[3H]NA释放刺激至对照水平的7倍。去除惊厥剂后，4-AP诱导的B-50磷酸化仍保持升高，这与用K + 去极化诱导的B-50磷酸化形成对比。在用4-AP孵育5分钟后，[3H]NA释放也观察到类似的持续增加。这些结果更深入地了解了4-AP诱导癫痫发生的分子机制，并为海马切片中B-50磷酸化与神经递质释放之间的相关性提供了进一步的证据。
