多巴胺 D 样受体在点燃大鼠深部脑刺激中的“去敏样效应”中的作用。
The role of dopamine D-like receptors in a "depotentiation-like effect" of deep brain stimulation in kindled rats.
机构信息
Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
Krembil Research Institute, University Health Network, Toronto, Canada.
出版信息
Brain Res. 2020 Jul 1;1738:146820. doi: 10.1016/j.brainres.2020.146820. Epub 2020 Apr 3.
The mechanisms involved in the anti-seizure effects of low-frequency stimulation (LFS) have not been completely determined. However, G-protein-coupled receptors, including D-like receptors, may have a role in mediating these effects. In the present study, the role of D-like receptors in LFS' anti-seizure action was investigated. Rats were kindled with semi-rapid (6 stimulations per day), electrical stimulation of the hippocampal CA1 area. In LFS-treated groups, subjects received four trials of LFS at 5 min, 6 h, 24 h, and 30 h following the last kindling stimulation. Each LFS set occurred at 5 min intervals, and consisted of 4 trains. Each train contained 200, 0/1 ms long, monophasic square wave pulses at 1 Hz. Haloperidol (D-like receptors antagonist, 2 µm) and/or bromocriptine (D-like receptors agonist 2 µg/µlit) were microinjected into the lateral ventricle immediately after the last kindling, before applying LFS. Obtained results showed that applying LFS in fully-kindled subjects led to a depotentiation-like decrease in kindling-induced potentiation and reduced the amplitude and rise slope of excitatory and inhibitory post-synaptic currents in whole-cell recordings from CA1 pyramidal neurons. In addition, LFS restored the kindling-induced, spatial learning and memory impairments in the Barnes maze test. A D-like receptor antagonist inhibited these effects of LFS, while a D-like receptor agonist mimicked these effects. In conclusion, a depotentiation-like mechanism may be involved in restoring LFS' effects on learning and memory, and synaptic plasticity. These effects depend on D-like receptors activity.
低频刺激(LFS)抗惊厥作用的机制尚未完全确定。然而,G 蛋白偶联受体,包括 D 样受体,可能在介导这些作用中发挥作用。在本研究中,研究了 D 样受体在 LFS 抗惊厥作用中的作用。大鼠通过半快速(每天 6 次刺激)电刺激海马 CA1 区被点燃。在 LFS 治疗组中,受试者在最后一次点燃刺激后 5 分钟、6 小时、24 小时和 30 小时接受 4 次 LFS 试验。每次 LFS 间隔 5 分钟,由 4 个训练组成。每个训练包含 200 个、0/1 ms 长、1 Hz 单相方波脉冲的 200 个、0/1 ms 长、1 Hz 单相方波脉冲。在最后一次点燃后,立即将氟哌啶醇(D 样受体拮抗剂,2 µm)和/或溴隐亭(D 样受体激动剂 2 µg/µlit)微注射到侧脑室中,然后应用 LFS。结果表明,在完全点燃的受试者中应用 LFS 导致点燃诱导的易化产生类似于去极化的减少,并降低 CA1 锥体神经元全细胞膜片钳记录中兴奋性和抑制性突触后电流的幅度和上升斜率。此外,LFS 恢复了巴恩斯迷宫测试中点燃诱导的空间学习和记忆障碍。D 样受体拮抗剂抑制了这些 LFS 的作用,而 D 样受体激动剂模拟了这些作用。总之,类似于去极化的机制可能参与恢复 LFS 对学习和记忆以及突触可塑性的作用。这些作用取决于 D 样受体的活性。