Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, pr. Torez 44, 194223, Saint Petersburg, Russia.
Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, pr. Torez 44, 194223, Saint Petersburg, Russia.
Biochem Biophys Res Commun. 2024 Nov 12;733:150666. doi: 10.1016/j.bbrc.2024.150666. Epub 2024 Sep 5.
Flufenamic acid (FFA) is an anti-inflammatory drug that affects multiple targets and is a widely used research tool in ion channel studies. This pharmacological compound has a low level of selectivity for the transient receptor potential (TRP) channel superfamily, blocking calcium-activated nonselective cation current (I) as well as afterdepolarizations (ADP) induced by it. A number of studies have demonstrated that FFA exerts an anti-epileptic effect in vitro, although the precise mechanism of this effect is not yet identified. The present study used whole-cell patch-clamp recordings and demonstrated that FFA (25 μM) can abolish the generation of seizure-like events (SLE) in entorhinal cortex slices perfused with a 4-aminopyridine-containing solution, depending on the time of application. FFA decreased the temporal summation of synaptic potentials at the onset of SLEs. However, as the epileptiform activity evolved and the SLE onset phase became more abrupt, the blocking effect of FFA diminished. FFA effectively abolished TRP channel-mediated slow ADPs, exerted a weak blockade and slowed the kinetics of GABAa receptor-mediated currents, and did not affect NMDA receptor-mediated evoked currents induced by extracellular stimulation. Although FFA did not directly inhibit NMDA receptor-mediated evoked currents, it decreased the summation of NMDA receptor-mediated potentials in a manner comparable to its effect on the initiation phase of SLE. This suggests that I blockade may be responsible for this effect. Furthermore, our results showed that the selective blocker of melastatin TRP channels (TRPM4) 9-phenanthrol effectively abolished epileptiform activity in a manner analogous to FFA. In contrast, ML-204, the blocker of canonical TRP channels (TRPC), had no discernible effect on this phenomenon. In conclusion, the study demonstrate that FFA abolishes epileptiform activity in the entorhinal cortex by blocking TRPM4 channels and, consequently, decreasing the effectiveness of temporal summation of glutamatergic potentials.
氟芬那酸（FFA）是一种影响多种靶点的抗炎药物，是离子通道研究中广泛使用的研究工具。这种药理化合物对瞬时受体电位（TRP）通道超家族的选择性较低，可阻断钙激活的非选择性阳离子电流（I）以及由其诱导的后去极化（ADP）。许多研究表明，FFA 在体外具有抗癫痫作用，尽管其确切机制尚不清楚。本研究使用全细胞膜片钳记录技术表明，FFA（25μM）可根据应用时间消除含有 4-氨基吡啶溶液灌流的内嗅皮质切片中癫痫样事件（SLE）的产生。FFA 降低了 SLE 发作时突触电位的时间总和。然而，随着癫痫样活动的发展和 SLE 起始阶段变得更加突然，FFA 的阻断作用减弱。FFA 有效消除了 TRP 通道介导的缓慢 ADP，对 GABAa 受体介导的电流表现出弱阻断作用并减慢其动力学，且不影响由细胞外刺激诱导的 NMDA 受体介导的诱发电流。尽管 FFA 没有直接抑制 NMDA 受体介导的诱发电流，但它以类似于对 SLE 起始阶段的影响的方式降低了 NMDA 受体介导的电位的总和。这表明 I 阻断可能是这种作用的原因。此外，我们的结果表明，亲环素 TRP 通道（TRPM4）的选择性阻断剂 9-菲咯啉（9-phenanthrol）可有效地消除癫痫样活动，其作用方式类似于 FFA。相比之下，经典 TRP 通道（TRPC）的阻断剂 ML-204 对这种现象没有明显影响。总之，该研究表明 FFA 通过阻断 TRPM4 通道消除内嗅皮质中的癫痫样活动，从而降低谷氨酸能电位时间总和的有效性。
