Bettini Ezio, Stahl Stephen M, De Martin Sara, Mattarei Andrea, Sgrignani Jacopo, Carignani Corrado, Nola Selena, Locatelli Patrizia, Pappagallo Marco, Inturrisi Charles E, Bifari Francesco, Cavalli Andrea, Alimonti Andrea, Pani Luca, Fava Maurizio, Traversa Sergio, Folli Franco, Manfredi Paolo L
In Vitro Pharmacology Department, Aptuit, An Evotec Company, 37135 Verona, Italy.
Department of Psychiatry, VAMC (SD), University of California, San Diego, CA 92093, USA.
Pharmaceuticals (Basel). 2022 Aug 13;15(8):997. doi: 10.3390/ph15080997.
Excessive Ca currents via N-methyl-D-aspartate receptors (NMDARs) have been implicated in many disorders. Uncompetitive NMDAR channel blockers are an emerging class of drugs in clinical use for major depressive disorder (MDD) and other neuropsychiatric diseases. The pharmacological characterization of uncompetitive NMDAR blockers in clinical use may improve our understanding of NMDAR function in physiology and pathology. REL-1017 (esmethadone-HCl), a novel uncompetitive NMDAR channel blocker in Phase 3 trials for the treatment of MDD, was characterized together with dextromethorphan, memantine, (±)-ketamine, and MK-801 in cell lines over-expressing NMDAR subtypes using fluorometric imaging plate reader (FLIPR), automated patch-clamp, and manual patch-clamp electrophysiology. In the absence of Mg, NMDAR subtypes NR1-2D were most sensitive to low, sub-μM glutamate concentrations in FLIPR experiments. FLIPR Ca determination demonstrated low μM affinity of REL-1017 at NMDARs with minimal subtype preference. In automated and manual patch-clamp electrophysiological experiments, REL-1017 exhibited preference for the NR1-2D NMDAR subtype in the presence of 1 mM Mg and 1 μM L-glutamate. Tau off and trapping characteristics were similar for (±)-ketamine and REL-1017. Results of radioligand binding assays in rat cortical neurons correlated with the estimated affinities obtained in FLIPR assays and in automated and manual patch-clamp assays. In silico studies of NMDARs in closed and open conformation indicate that REL-1017 has a higher preference for docking and undocking the open-channel conformation compared to ketamine. In conclusion, the pharmacological characteristics of REL-1017 at NMDARs, including relatively low affinity at the NMDAR, NR1-2D subtype preference in the presence of 1 mM Mg, tau off and degree of trapping similar to (±)-ketamine, and preferential docking and undocking of the open NMDAR, could all be important variables for understanding the rapid-onset antidepressant effects of REL-1017 without psychotomimetic side effects.
通过N-甲基-D-天冬氨酸受体（NMDARs）的过量钙电流与许多疾病有关。非竞争性NMDAR通道阻滞剂是一类新兴的药物，正在临床上用于治疗重度抑郁症（MDD）和其他神经精神疾病。对临床使用的非竞争性NMDAR阻滞剂进行药理学特征分析，可能会增进我们对NMDAR在生理和病理过程中功能的理解。REL-1017（盐酸艾司美沙酮）是一种新型的非竞争性NMDAR通道阻滞剂，正在进行治疗MDD的3期试验，我们使用荧光成像微孔板读数仪（FLIPR）、自动膜片钳和手动膜片钳电生理学技术，在过表达NMDAR亚型的细胞系中，对其与右美沙芬、美金刚、（±）-氯胺酮和MK-801进行了特征分析。在不存在镁离子的情况下，在FLIPR实验中，NMDAR亚型NR1-2D对低浓度、亚微摩尔浓度的谷氨酸最为敏感。FLIPR钙测定表明，REL-1017在NMDAR上具有低微摩尔亲和力，且对亚型的偏好最小。在自动和手动膜片钳电生理实验中，在存在1 mM镁离子和1 μM L-谷氨酸的情况下，REL-1017表现出对NR1-2D NMDAR亚型的偏好。（±）-氯胺酮和REL-1017的τ关闭和捕获特性相似。大鼠皮质神经元的放射性配体结合试验结果与在FLIPR试验以及自动和手动膜片钳试验中获得的估计亲和力相关。对处于关闭和开放构象的NMDAR进行的计算机模拟研究表明，与氯胺酮相比，REL-1017对开放通道构象的对接和解离具有更高的偏好性。总之，REL-1017在NMDAR上的药理学特征，包括在NMDAR上相对较低的亲和力、在存在1 mM镁离子时对NR1-2D亚型的偏好、与（±）-氯胺酮相似的τ关闭和捕获程度，以及对开放NMDAR的优先对接和解离，所有这些都可能是理解REL-1017无拟精神病副作用的快速起效抗抑郁作用的重要变量。
