Recovery of cerebral cortex from asphyxiation

¹ Kerckhoff Laboratories of the Biological Sciences, California Institute of Technology, Pasadena, California

Cerebral asphyxiation causes, after a latency of 2–3 min, a marked increase in cortical impedance, a transport of chloride (probably accompanied by sodium) into apical dendrites and a swelling of these structures. The reversibility of these changes was investigated by reoxygenating the brain for 15 min after periods of asphyxiation ranging from 15 to 75 min. All the asphyxial changes were in part of the experiments completely reversed by reoxygenation after circulatory arrests up to 60 min in duration. The course of the impedance changes showed this active removal to occur during the first 5–10 min of reoxygenation. Even after asphyxiations of long duration electrolytes can thus be removed actively from cellular elements. In part of the experiments abnormal amounts of chloride were found after reoxygenation in the apical dendrites although the cortical impedance and the dendritic diameter had reverted to preasphyxial values, indicating that in these experiments sodium had been removed in combination with an anion other than chloride.