Sodium thiopental, used in a narcotic dose, makes it possible to identify the\nnervous processes that underlie consciousness and establish the causes of its\ndisorder. When studying the cortical EEG activity, the impulses of individual\nnerve cells and the electromyographic activity of the muscles of the forelimb,\nit was found that thiopental blocks a number of neuronal reactions requiring\nenergy support: tonic activating reactions to acetylcholine, applied to neurons,\ncease; the rate of spontaneous neuronal activity drops; the stage of\nnon-specific activation in response to electrocutaneous stimulation disappears.\nSo, thiopental blocks consciousness by significant limitation of the\nbrain energy metabolism. This results in a loss of the adaptive function of the\ncentral nervous system. At the same time, glutamatergic excitation, the formation\nof which does not depend on energy support, is resistant to the action\nof thiopental. The blocking of the brainâ??s energy supply caused by thiopental,\nin accordance with its depth, develops in two stages-hypoxic and narcotic.\nThe hypoxic stage is accompanied by hyperactivity in the nervous system,\nwhich is manifested by epileptiform discharges on the EEG and powerful\nunmotivated movement; the narcotic stage is associated with blockade of\nmotor activity and flattening of EEG oscillations. The post-narcotic state associated\nwith the consequence of the hypoxic effect of thiopental leads to the\nloss of ionic homeostasis and is accompanied by a steady drop in the amplitude\nof cortical neuron spikes.
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