While the prevalence and the use of new psychoactive substances (NPS) is steadily increasing, data on pharmacological, toxicological and clinical effects is limited. Considering the large number of NPS available, there is a clear need for efficient in vitro screening techniques that capture multiple mechanisms of action. Neuronal cultures grown on multi-well microelectrode arrays (mwMEAs) have previously proven suitable for neurotoxicity screening of chemicals, pharmaceuticals and (illicit) drugs. We therefore used rat primary cortical cultures grown on mwMEA plates to investigate the effects of eight NPS (PMMA, α-PVP, methylone, MDPV, 2C-B, 25B-NBOMe, BZP and TFMPP) and two ‘classic’ illicit drugs (cocaine, methamphetamine) on spontaneous neuronal activity.

All tested drugs rapidly and concentration-dependently decreased the weighted mean firing rate (wMFR) and the weighted mean burst rate (wMBR) during a 30 min acute exposure. Of the ‘classic’ drugs, cocaine most potently inhibited the wMFR (IC₅₀ 9.8 μM), whereas methamphetamine and the structurally-related NPS PMMA were much less potent (IC₅₀ 100 μM and IC₅₀ 112 μM, respectively). Of the cathinones, MDPV and α-PVP showed comparable IC₅₀ values (29 μM and 21 μM, respectively), although methylone was 10-fold less potent (IC₅₀ 235 μM). Comparable 10-fold differences in potency were also observed between the hallucinogenic phenethylamines 2C-B (IC₅₀ 27 μM) and 25B-NBOMe (IC₅₀ 2.4 μM), and between the piperazine derivatives BZP (IC₅₀ 161 μM) and TFMPP (IC₅₀ 19 μM). All drugs also inhibited the wMBR and concentration-response curves for wMBR and wMFR were comparable.

For most drugs, IC₅₀ values are close to the estimated human brain concentrations following recreational doses of these drugs, highlighting the importance of this efficient in vitro screening approach for classification and prioritization of emerging NPS. Moreover, the wide range of IC₅₀ values observed for these and previously tested drugs of abuse, both within and between different classes of NPS, indicates that additional investigation of structure-activity relationships could aid future risk assessment of emerging NPS.

尽管新型精神活性物质（NPS）的流行和使用在稳步增加，但有关药理，毒理学和临床作用的数据仍然有限。考虑到可用的NPS数量众多，显然需要有效的体外筛选技术来捕获多种作用机制。先前已证明，在多孔微电极阵列（mwMEA）上生长的神经元培养物适用于筛选化学药品，药物和（非法）药物的神经毒性。因此，我们使用在mwMEA板上生长的大鼠原代皮层培养物研究了8种NPS（PMMA，α-PVP，甲酮，MDPV，2C-B，25B-NBOMe，BZP和TFMPP）和两种“经典”非法药物（可卡因）的作用。 （甲基苯丙胺）对自然神经元活性的影响。

在30分钟的急性暴露过程中，所有测试药物均迅速且浓度依赖性地降低了加权平均射击率（wMFR）和加权平均爆发率（wMBR）。在“经典”药物中，可卡因对wMFR的抑制作用最强（IC ₅₀ 9.8μM ），而甲基苯丙胺和与结构相关的NPS PMMA的抑制作用要低得多（分别为IC ₅₀ 100μM和IC ₅₀ 112μM）。在二氢呋喃酮中，MDPV和α-PVP的IC ₅₀值相近（分别为29μM和21μM），尽管甲酮的效价低了10倍（IC ₅₀ 235μM ）。在致幻的苯乙胺2C-B（IC ₅₀ 27μM）和25B-NBOMe（IC₅₀ 2.4μM）和哌嗪衍生物BZP（IC ₅₀ 161μM）和TFMPP（IC ₅₀ 19μM ）之间。所有药物也均抑制了wMBR，并且wMBR和wMFR的浓度-反应曲线相当。

对于大多数药物，IC ₅₀值接近这些药物的休闲剂量后的估计人脑浓度，突显了这种有效的体外筛选方法对于新兴NPS的分类和优先级排序的重要性。此外，在不同类别的NPS内和之间，针对这些药物和先前测试的滥用药物观察到的IC ₅₀值范围很广，这表明对结构活性关系的进一步研究可能有助于将来对新兴NPS进行风险评估。