Chatt A B, Ebersole J S
Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06510.
Exp Neurol. 1989 Jan;103(1):105-9. doi: 10.1016/0014-4886(89)90192-1.
The direct excitatory glutamate analog, kainic acid, when injected into different layers of the cat visual cortex, has two effects on this tissue that are fundamentally different from those exerted by the disinhibitory agents penicillin, bicuculline, and strychnine. First, both concentration-dependent suppression and convulsant activity was seen. Second, these concentration-dependent influences were produced effectively in each cortical layer challenged despite a reported preferential localization of kainic acid receptors to layer 6. In contrast, the disinhibitory agents generally produce only convulsant effects, do so in a laminar-specific manner, and at significantly lower concentrations in intact brain (i.e., 50 microM vs 15 mM). These results suggest that kainic acid, in the concentrations employed here, has a generalized excitatory effect on all cortical circuitry and that it's convulsant influences are nonspecific and less potent than those of the inhibitory blockers. Further, a common neural trait shared by these different modes of epileptogenesis is discussed.
直接兴奋性谷氨酸类似物 kainic 酸，当注入猫视觉皮层的不同层时，对该组织有两种作用，这与去抑制性药物青霉素、荷包牡丹碱和士的宁所产生的作用根本不同。首先，观察到了浓度依赖性抑制和惊厥活性。其次，尽管有报道称 kainic 酸受体优先定位于第 6 层，但在每个受到挑战的皮层层中都有效地产生了这些浓度依赖性影响。相比之下，去抑制性药物通常只产生惊厥作用，以层特异性方式产生，并且在完整大脑中的浓度显著更低（即 50 microM 对 15 mM）。这些结果表明，这里使用的浓度的 kainic 酸对所有皮层回路具有普遍的兴奋作用，并且其惊厥影响是非特异性的，且比抑制性阻滞剂的作用效力更低。此外，还讨论了这些不同癫痫发生模式共有的一个共同神经特征。
