Chebabo S R, Do Carmo R J
Instituto de Biofísica Carlos Chagas Filho, Departamento de Neurobiologia, Cidade Universitária-Ilha do Fundão, Rio de Janeiro, Brazil.
Brain Res. 1991 Jun 14;551(1-2):16-9. doi: 10.1016/0006-8993(91)90907-d.
Several studies indicate that spreading depression is fundamentally related to seizure marches and to the aura of classical migraine. Moreover, recent investigations call attention to its possible relevance in clinical disturbances associated with brain ischemia, trauma, and hypoglycemia. The anticonvulsant phenytoin has been shown to protect the nervous tissue from the effects of anoxia and ischemia. These properties suggest that phenytoin should be able to counteract spreading depression. Therefore, we investigated its effect on spreading depression elicited by mechanical or chemical (KCl) stimulation, in isolated chick retinas. The results showed that phenytoin: (1) increases the threshold concentration of KCl to initiate the phenomenon; (2) decreases the velocity of propagation of spreading depression; (3) shortens considerably the duration of the slow potential, ionic (K+, Ca2+, Cl-), and volume changes of the extracellular compartment during spreading depression. Possible mechanisms underlying the observed effects are discussed.
多项研究表明，扩散性抑制与癫痫发作进展以及经典偏头痛的先兆从根本上相关。此外，最近的研究提醒人们注意其在与脑缺血、创伤和低血糖相关的临床紊乱中可能具有的相关性。抗惊厥药物苯妥英已被证明能保护神经组织免受缺氧和缺血的影响。这些特性表明苯妥英应该能够对抗扩散性抑制。因此，我们在离体鸡视网膜中研究了其对机械或化学（氯化钾）刺激引发的扩散性抑制的影响。结果表明，苯妥英：（1）提高引发该现象的氯化钾阈值浓度；（2）降低扩散性抑制的传播速度；（3）显著缩短扩散性抑制期间细胞外区室的慢电位、离子（钾离子、钙离子、氯离子）和体积变化的持续时间。文中讨论了所观察到的效应背后可能的机制。
