Sutula T, Steward O
Department of Neurology, University of Wisconsin, Madison 53792.
Brain Res. 1987 Sep 8;420(1):109-17. doi: 10.1016/0006-8993(87)90245-9.
Previous studies have revealed that a form of synaptic potentiation resembling long-term potentiation (LTP) occurs at various sites as a result of stimulation that leads to kindling. The present study evaluates what role this synaptic potentiation plays in the development of kindling following periodic stimulation of the entorhinal cortex of the rat. LTP was repetitively induced in the pathway from the entorhinal cortex (EC) to the dentate gyrus (DG) by daily stimulation with high frequency trains that led to LTP, but did not evoke afterdischarge (AD). Subsequently, animals received stimulation designed to induce kindling (that led to AD), and this stimulation was delivered once per day until kindled seizures were induced. While repetitive induction of LTP was not sufficient to produce kindling, prior induction of LTP significantly increased the rate of subsequent kindling as evidenced by a decrease in the number of kindling stimulations required to induce the kindled state. As a group, animals that had received stimulation designed to induce LTP developed kindled seizures after an average of 10 AD's, whereas a control group that had received non-potentiating stimulation required 25 AD's. These results indicate that LTP at EC-DG synapses cannot represent the mechanism of kindling following EC stimulation. However, synaptic potentiation at this site can facilitate the development of epileptogenesis in response to subsequent activation of the perforant path.
先前的研究表明，一种类似于长时程增强（LTP）的突触增强形式会在各种部位因导致点燃的刺激而出现。本研究评估了这种突触增强在对大鼠内嗅皮质进行周期性刺激后点燃发展过程中所起的作用。通过每日用高频串刺激诱导从内嗅皮质（EC）到齿状回（DG）通路中的LTP，但不诱发后放电（AD）。随后，动物接受旨在诱导点燃（导致AD）的刺激，且该刺激每天给予一次，直到诱发点燃性癫痫发作。虽然重复诱导LTP不足以产生点燃，但LTP的预先诱导显著提高了随后点燃的速率，这一点可通过诱导点燃状态所需的点燃刺激次数减少得以证明。作为一个群体，接受旨在诱导LTP刺激的动物在平均10次AD后出现点燃性癫痫发作，而接受非增强刺激的对照组则需要25次AD。这些结果表明，EC-DG突触处的LTP不能代表EC刺激后点燃的机制。然而，该部位的突触增强可促进对随后穿通通路激活的癫痫发生发展。
