Abstract
The use of pentamethylene tetrazol (metrazol) and insulin shock therapy in schizophrenia has prompted several investigations in this laboratory upon the actions of these agents given in convulsive doses. This report deals with some of these actions upon the potentials recorded from the intact rabbit cortex.
Recordings have been made with electrodes of the type described by Rheinberger and Jasper 1 placed symmetrically on the precentral and striate areas of the rabbit. Potentials were led through condenser coupled amplifiers to moving coil oscillographs. Other records were made with paired silver tube electrodes (Adrian) 2 following trephination. Curare and artificial respiration have been used in experiments with metrazol to obviate the gross movement artefacts, but with insulin, the use of curare has been found impractical, due to its hyperglycemic action, which prevented the occurrence of convulsions in all our earlier experiments.
Metrazol. Fig. 1 shows a continuous record of the average metrazol convulsions, the potentials being recorded with paired leads on the area striata. There are 4 clearly defined phases following the latent period, which varies from 3-12 seconds. Phase 1 lasts from 2-21 seconds in primary convulsions and has a wave form very close to that recorded in human petit mal epilepsy. This phase is usually absent in the later secondary convulsions which often occur. Phase 2 lasts from 23-75 seconds, phase 3 from 0-13 seconds, while phase 4 is prolonged, lasting for one hour and up.
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