Noebels J L, Pedley T A
Brain Res. 1977 Apr 15;125(2):293-303. doi: 10.1016/0006-8993(77)90622-9.
14C-labeled penicillin was topically applied to the suprasylvian gyri of adult cats in order to study the distribution of the convulsant agent at the onset of focal epileptogenesis. Using radioassay and autoradiographic techniques, a steep gradient of penicillin was found. At the time interictal EEG spike discharges appeared, 95% of the labeled drug was in the uppermost cortical layers (laminae I-III). Analysis of the concentration profiles obtained by scintillation counting showed that penetration of penicillin into brain occurs primarily by passive diffusion. An apparent diffusion coefficient for penicillin in neocortex of 1.5 sq. mm/h was calculated using modifications of standard diffusion equations. It is apparent that with a rapidly acting topical convulsant such as penicillin, the dimensions of the neuronal pool actually in contact with the drug will change significantly over time. The changing boundaries of the epileptic neuronal aggregate must be taken into account when interpreting observations made within and around such experimentally produced epileptic foci.
将14C标记的青霉素局部应用于成年猫的上薛氏回，以研究惊厥剂在局灶性癫痫发作起始时的分布。使用放射分析和放射自显影技术，发现青霉素存在陡峭的梯度。在发作间期脑电图尖峰放电出现时，95%的标记药物位于最上层皮质层（I-III层）。通过闪烁计数获得的浓度曲线分析表明，青霉素进入大脑主要通过被动扩散。使用标准扩散方程的修正方法计算出青霉素在新皮质中的表观扩散系数为1.5平方毫米/小时。显然，对于像青霉素这样作用迅速的局部惊厥剂，实际与药物接触的神经元池的大小会随时间显著变化。在解释在此类实验性癫痫病灶内部及周围所做的观察结果时，必须考虑癫痫神经元聚集体不断变化的边界。
