Abstract
THIS is a study primarily of the effect of electroshock on the major components of the energy reserve in brain. Specifically ATP, P-creatine, glucose, glycogen and lactate were measured with particular emphasis on the time course of any changes and on the influence of anaesthetic or depressant drugs. For comparison data are included from animals undergoing seizures induced by pentylenetetrazole or insulin. There have been many previous studies of changes in components of the energy reserve during convulsive activity. In spite of this there remain uncertainties as to the sequence of events, the influence of depressants, and differences in response to different convulsive agents. Most early studies were carried out with large animals. Because of the slowness with which a large head freezes, it was usually necessary to expose the brain under anaesthesia and either conduct the experiment in the presence of the anaesthetic or to administer a neuromuscular blocking agent and wait for the anaesthetic to dissipate (STONE, WEBSTER and GURDJIAN, 1945; KLEIN and OLSEN, 1947; BAIN, POLLOCK and STEIN, 1949; TEWS, CARTER and STONE, 1965). Some studies have been carried out with rats or mice, but, because of the limited amount of material or for other reasons, analyses have usually not been complete (DAWSON and RICHTER, 1950; CARTER and STONE, 1961; TARR, BRADA and SAMPSON, 1962; MINARD and DAVIS, 1962). Mice were used for the present experiments, and efforts were made to freeze the brain as rapidly as possible at the appropriate time. In addition only cerebral cortex was used since this is the first part to freeze. Preparation of material. Adult male white mice were used throughout unless otherwise noted. When a drug was given, this was injected intraperitoneally in approximately 0-2 ml of solution. At the desired moment each mouse was plunged into Freon-12 (CCI,F2) that had been brought to its freezing point (-150°) with liquid N. Rapid freezing was promoted by vigorous agitation in the Freon. For the electrical stimulation experiments current was applied through metal electrodes, coated with Redox paste, and held firmly, bilaterally, just anterior to the cars. Unidirectional rectangular pulses, 150 v, 1 msec, at a frequency of 150/sec were supplied for 1 sec by a Grass S, apparatus. În control mice, electrodes were held in place briefly but no stimulus was applied.
View more >>