Kulagina Nadezhda V, O'shaughnessy Thomas J, Ma Wu, Ramsdell John S, Pancrazio Joseph J
Center for BioMolecular Science and Engineering, Code 6900, Naval Research Laboratory, 4555 Overlook Avenue, Washington, DC 20375, USA.
Toxicon. 2004 Nov;44(6):669-76. doi: 10.1016/j.toxicon.2004.07.023.
Brevetoxins and saxitoxins (STXs), which are produced by marine dinoflagellates, are very potent neurotoxins targeting separate sites of the alpha subunit of voltage-dependent sodium channels (VDSCs). An attractive approach for marine toxin detection relies on pharmacological modulation of VDSCs expressed in cells or tissues. While these function-based cellular assays exhibit the required sensitivity, they are typically slow and have limited potential use for field applications. Cultured neuronal networks grown on substrate integrated microelectrode arrays (MEAs) have emerged as a robust and sensitive approach for environmental threat detection. The present work describes the rapid effects of brevetoxin-2 (PbTx-2) and STX on embryonic murine frontal cortex neuronal networks on MEAs. Network recording parameters such as mean spike rate, burst rate, burst duration, number of spikes per burst and spike amplitude were analyzed before and after exposure to the toxins. STX produced fast and reversible inhibition of all electrophysiological parameters with IC(50)s ranging between 1.2 and 2.2nM. Although PbTx-2 also caused inhibition of most of the network electrophysiological parameters, it produced an increase in burst duration at lower concentrations (EC(50)=15+/-2 nM, n=4) followed by inhibition at higher ones (IC(50)=63+/-4 nM, n=4). Exposure of frontal cortex networks to PbTx-2 and STX also caused differential effects on spike amplitude. This work demonstrates that cultured neuronal networks not only could be used for pharmacological characterization of marine toxins but they also provide a tool with unique properties for their detection.
短裸甲藻毒素和石房蛤毒素（STXs）由海洋甲藻产生，是非常强效的神经毒素，作用于电压依赖性钠通道（VDSCs）α亚基的不同位点。一种有吸引力的海洋毒素检测方法依赖于对细胞或组织中表达的VDSCs进行药理学调节。虽然这些基于功能的细胞检测方法具有所需的灵敏度，但它们通常速度较慢，在现场应用中的潜在用途有限。在集成微电极阵列（MEA）上生长的培养神经元网络已成为一种强大而灵敏的环境威胁检测方法。本研究描述了短裸甲藻毒素-2（PbTx-2）和STX对MEA上胚胎小鼠额叶皮质神经元网络的快速影响。在暴露于毒素之前和之后，分析了网络记录参数，如平均放电率、爆发率、爆发持续时间、每次爆发的尖峰数和尖峰幅度。STX对所有电生理参数产生快速且可逆的抑制作用，半数抑制浓度（IC50）在1.2至2.2 nM之间。虽然PbTx-2也导致大多数网络电生理参数受到抑制，但在较低浓度下（半数有效浓度[EC50]=15±2 nM，n = 4）它会使爆发持续时间增加，随后在较高浓度下产生抑制作用（IC50 = 63±4 nM，n = 4）。额叶皮质网络暴露于PbTx-2和STX也对尖峰幅度产生了不同的影响。这项工作表明，培养的神经元网络不仅可用于海洋毒素的药理学特征分析，还为其检测提供了一种具有独特特性的工具。
