Sparing of metabolic stress in Purkinje cells after maximal electroshock

Experimental seizures were induced in mice by application of 50 mA for 0.2 sec via corneal electrodes. The reproducible conclusive behavior was characterized by a sequence of 2 sec of tonic flexion, 13 sec of tonic extension, and 8 sec of clonus followed by a postictal depressive stage. The animals were frozen and tissues were prepared for analysis according to Lowry and Passonneau [Lowry, O. H. & Passonneau, J. V. (1972) A Flexible System of Enzymatic Analysis (Academic, New York)]. Freeze-dried samples (1-10 ng) of pyramidal cell bodies and adjacent neuropil from the parietal cortex and of Purkinje cell bodies and adjacent neuropil from the cerebellum were analyzed for glucose, ATP, and P-creatine (0.01-0.05 pmol). There were marked decreases in these energy stores after the maximal electroshock in three of the areas examined. In the Purkinje cell bodies, however, the metabolic stress was dampened; glucose concentrations decreased, but the levels of ATP were maintained and, to a lesser extent, those of P-creatine. The results indicate that the output from the Purkinje cells is less than in the other regions examined in the excitable stages of the convulsion. The lesser energy debt probably reflects lower energy demand as well as a lower discharge intensity. The fact that Purkinje cells are spared from the metabolic stress imposed on other regions may be a partial explanation of the seizure activity. A diminished output from the Purkinje cells could be a situation that permits cortical convulsive activity.