Department of Pharmacology and Neuroscience, Creighton University, Omaha, NE 68123, USA.
Center for Marine Biotechnology & Biomedicine, Scripps Institution of Oceanography, San Diego, La Jolla, CA 92093, USA.
Mar Drugs. 2020 Jul 21;18(7):374. doi: 10.3390/md18070374.
Emerging literature suggests that after a stroke, the peri-infarct region exhibits dynamic changes in excitability. In rodent stroke models, treatments that enhance excitability in the peri-infarct cerebral cortex promote motor recovery. This increase in cortical excitability and plasticity is opposed by increases in tonic GABAergic inhibition in the peri-infarct zone beginning three days after a stroke in a mouse model. Maintenance of a favorable excitatory-inhibitory balance promoting cerebrocortical excitability could potentially improve recovery. Brevetoxin-2 (PbTx-2) is a voltage-gated sodium channel (VGSC) gating modifier that increases intracellular sodium ([Na]i), upregulates N-methyl-D-aspartate receptor (NMDAR) channel activity and engages downstream calcium (Ca) signaling pathways. In immature cerebrocortical neurons, PbTx-2 promoted neuronal structural plasticity by increasing neurite outgrowth, dendritogenesis and synaptogenesis. We hypothesized that PbTx-2 may promote excitability and structural remodeling in the peri-infarct region, leading to improved functional outcomes following a stroke. We tested this hypothesis using epicortical application of PbTx-2 after a photothrombotic stroke in mice. We show that PbTx-2 enhanced the dendritic arborization and synapse density of cortical layer V pyramidal neurons in the peri-infarct cortex. PbTx-2 also produced a robust improvement of motor recovery. These results suggest a novel pharmacologic approach to mimic activity-dependent recovery from stroke.
新的文献表明,中风后,梗塞周围区域的兴奋性会发生动态变化。在啮齿动物中风模型中,增强梗塞周围大脑皮层兴奋性的治疗方法可促进运动功能恢复。在中风后三天的小鼠模型中,梗塞周围区域的紧张性 GABA 抑制增加,这与皮层兴奋性和可塑性的增加相反。维持有利于促进大脑皮质兴奋性的兴奋-抑制平衡可能有助于恢复。短裸甲藻毒素-2(PbTx-2)是一种电压门控钠离子通道(VGSC)门控调节剂,可增加细胞内钠离子([Na]i),上调 N-甲基-D-天冬氨酸受体(NMDAR)通道活性,并参与下游钙(Ca)信号通路。在未成熟的大脑皮质神经元中,PbTx-2 通过增加轴突生长、树突生成和突触生成来促进神经元结构可塑性。我们假设 PbTx-2 可能会促进梗塞周围区域的兴奋性和结构重塑,从而改善中风后的功能结果。我们通过在小鼠光血栓性中风后对大脑皮质进行 PbTx-2 进行皮内应用来验证这一假说。我们发现 PbTx-2 增强了梗塞周围皮质层 V 锥体神经元的树突分支和突触密度。PbTx-2 还产生了运动功能恢复的显著改善。这些结果表明,这是一种模仿中风后活动依赖性恢复的新型药物治疗方法。