Chang Michael, Dufour Suzie, Carlen Peter L, Valiante Taufik A
Division of Fundamental Neurobiology, Krembil Research Institute; Institute of Medical Science, Faculty of Medicine, University of Toronto.
Division of Fundamental Neurobiology, Krembil Research Institute; Institute of Biomaterials and Biomedical Engineering, University of Toronto.
J Vis Exp. 2019 Jan 19(143). doi: 10.3791/57952.
Controlling seizures remains a challenging issue for the medical community. To make progress, researchers need a way to extensively study seizure dynamics and investigate its underlying mechanisms. Acute seizure models are convenient, offer the ability to perform electrophysiological recordings, and can generate a large volume of electrographic seizure-like (ictal) events. The promising findings from acute seizure models can then be advanced to chronic epilepsy models and clinical trials. Thus, studying seizures in acute models that faithfully replicate the electrographic and dynamical signatures of a clinical seizure will be essential for making clinically relevant findings. Studying ictal events in acute seizure models prepared from human tissue is also important for making findings that are clinically relevant. The key focus in this paper is on the cortical 4-AP model due to its versatility in generating ictal events in both in vivo and in vitro studies, as well as in both mouse and human tissue. The methods in this paper will also describe an alternative method of seizure induction using the Zero-Mg model and provide a detailed overview of the advantages and limitations of the epileptiform-like activity generated in the different acute seizure models. Moreover, by taking advantage of commercially available optogenetic mouse strains, a brief (30 ms) light pulse can be used to trigger an ictal event identical to those occurring spontaneously. Similarly, 30 - 100 ms puffs of neurotransmitters (Gamma-Amino Butyric Acid or glutamate) can be applied to the human tissue to trigger ictal events that are identical to those occurring spontaneously. The ability to trigger ictal events on-demand in acute seizure models offers the newfound ability to observe the exact sequence of events that underlie seizure initiation dynamics and efficiently evaluate potential anti-seizure therapies.
对医学界来说，控制癫痫发作仍然是一个具有挑战性的问题。为取得进展，研究人员需要一种方法来广泛研究癫痫发作动态并探究其潜在机制。急性癫痫发作模型很方便，具备进行电生理记录的能力，并且能够产生大量脑电图癫痫样（发作期）事件。然后，急性癫痫发作模型中获得的有前景的发现可以推进到慢性癫痫模型和临床试验中。因此，在能忠实地复制临床癫痫发作的脑电图和动态特征的急性模型中研究癫痫发作，对于获得与临床相关的发现至关重要。在由人体组织制备的急性癫痫发作模型中研究发作期事件，对于获得与临床相关的发现也很重要。由于其在体内和体外研究以及在小鼠和人体组织中产生发作期事件的多功能性，本文的重点是皮质4-氨基吡啶（4-AP）模型。本文中的方法还将描述使用零镁模型诱导癫痫发作的另一种方法，并详细概述在不同急性癫痫发作模型中产生的癫痫样活动的优缺点。此外，利用市售的光遗传学小鼠品系，一个短暂的（30毫秒）光脉冲可用于触发与自发发生的事件相同的发作期事件。同样，可将30 - 100毫秒的神经递质（γ-氨基丁酸或谷氨酸）吹入人体组织，以触发与自发发生的事件相同的发作期事件。在急性癫痫发作模型中按需触发发作期事件的能力，提供了观察癫痫发作起始动态背后的确切事件序列并有效评估潜在抗癫痫疗法的新能力。
