ABSTRACT
The effect of atmospheric contaminants on animals exposed to prolonged hypokinesia was investigated. A quantitative correlation between the resistance and the concentration of an atmospheric contaminant (sulfur oxide-SO2) was established, using concentration-time and concentration-effect relations.
Subject(s)
Sulfur Dioxide/toxicity , Air Pollutants/toxicity , Animals , Dose-Response Relationship, Drug , Male , Rats , Restraint, Physical , Time FactorsABSTRACT
The task of the second stage of Soviet-American cooperation on the problem of environmental health science was to explain the question of the comparative sensitivity of methods used in both countries, as well as the indices of harmful effects for the same toxic substance (carbon disulfide), with the purpose of determining the most informative methods of assessing the influence of atmospheric pollutants on organisms. The application of neurophysiological research methods (recording total electrical activity of the cortex and cortical structures of the brain, studying amplitude-time characteristics of averaged evoked potentials of the optical cortex, investigating sensory and convulsive thresholds) has made it possible to explain the neurophysiological basis of the effect of carbon disulfide on the central nervous system-the perturbation of cortical inhibition processes and the increase of excitation in amygdalate structures, both of which play an important role in the fixation process of temporary connection. The compilation of data from neurophysiological and neurochemical investigations show that neurophysiological changes are associated primarily with a decrease in enzymic breakdown of free neuraminic acid. The study of the average evoked potentials in humans during exposure to carbon disulfide concentrations of 0.09 mg/m(3) revealed a tendency to decrease the short latent amplitude components and increase the long latent amplitude components of the averaged evoked potentials. The study of operant behavior in rats revealed a characteristic change in the instrumental alimentary reactions under long-term (3 months) exposure of carbon disulfide to a concentration of 16 mg/m(3). IN THIS MANNER, THE FOLLOWING WERE DEVELOPED IN EXPERIMENTS WITH ANIMALS AND RESEARCH ON HUMANS: indices of the harmful effects of neurotropic toxic substances, a change in operant behavior, a decrease in the amplitude of total electrical activity, a change in time-amplitude parameters of evoked potentials, and a decrease in post-discharge convulsion thresholds in the cortical-medial nucleus of the amygdala. Neurophysiological and neurochemical research methods have proven to be the most sensitive and informative of the methods used. These criteria and methods are recommended for determining threshold levels of various neurotropic toxic substances which pollute the atmosphere.
Subject(s)
Brain/drug effects , Carbon Disulfide/toxicity , Animals , Brain/enzymology , Brain/metabolism , Environmental Exposure , Evoked Potentials/drug effects , Humans , Neuraminic Acids/blood , Neuraminic Acids/metabolism , Rabbits , Sialic Acids/blood , Sialic Acids/metabolism , Visual Cortex/drug effectsSubject(s)
Calcium/metabolism , Child , Humans , Lactates/metabolism , Moscow , Phosphorus/metabolism , Ukraine , Urban Population , Water SupplyABSTRACT
Some aspects of the mechanism of action of atmospheric pollutants (acetone, benzene, ammonia, formaldehyde, and ozone) on the central nervous system were studied by using methods of functional electroencephalography (analysis of the readjustment reaction to a rhythmic light stimulus, evoked potentials of the cerebral cortex, and determination of the photometrazol thresholds). Effects of the compounds were determined for the various structures of the cerebral cortex of experimental animals. The most sensitive structures were those which were first to associate in the reaction to toxic agents (the corticomedial nucleus of the amygdaloid complex and the olfactory bulb). EEG indices were observed which were indicative of an adverse effect (epileptoid activity in the most sensitive formations of the brain and a stable generalized stress rhythm in the neocortex and in the limbic ascending reticular system). During long-term action of toxic materials at low concentrations, changes were observed in the parameters of the primary and secondary responses of the visual evoked potential which were indicative of a disturbance of the cortical inhibition processes. This can be considered one effect of atmospheric pollutants at low concentrations. Problems of the comparative sensitivity of the various methods of studying the central nervous system are being investigated with a single compound: carbon bisulfide. In human experiments concerned with the fine coordination of measured movements such as writing and the solution of arithmetic problems, the subject-operator observed that repeated inhalation of subsensory concentrations of carbon bisulfide (0.08 mg/m3 level) disturbs the rate of execution of assigned motor processes. In tests with rats with developed instrument conditioned reflexes, it was shown that entire behavioral acts deteriorate under the effect of the same carbon bisulfide concentration. In tests on rabbits, simultaneous neurophysiological and neurochemical analyses were performed on the changes in the functional state of the central nervous system under chronic exposure to carbon bisulfide at various concentrations.
