Comparative study covered influence of toluene on behavioral parameters, cognitive abilities and brain bioelectric activity in white rats with normal embryonic development or with prenatal hypoxia. Prenatal hypoxia was simulated by subcutaneous injection of 50 mg/kg sodium nitrite into female white rats on day 13-14 of gestation. The offspring at the age of 2, 5-3 months was exposed to toluene (concentration of 560 mg/m3, 4 hours per day, 5 days per week, over 4 weeks). After the exposure, the animals were estimated for individual and intraspecific behaviour in "open fields and "resident-intruder" tests, for cognitive abilities in "radial maze" training, EEG with visual and auditory evoked potentials. Acute hypoxia at early stages of organogenesis appeared to be burdening factor and to influence consequences of toluene intoxication.

The authors presented results of experimental studies assessing influence of vibration on white rats. Dynamics of morphologic changes development in brain of experimental animals exposed to vibration were shown. Exposure to vibration in white rats daily during 4 hours over 15 days causes astrogliosis--compensation process in response to brain injury; over 1 month--causes morphologic brain changes (vacuoles formation in neuropile, decrease in astroglia cells number); over 2 months--causes lower plasticity of brain neurons, preserved astrogliosis; over 4 months--causes perivascular edema. Changes in brain bioelectric activity indicate stages of pathologic process in central nervous system. Increase in vibration exposure duration leads to more severe diffuse pathologic changes in brain and local cortical and diencephalic disorders. Exposure to vibration in white rats causes increase in general mobility, nonspecific activation of behaviour, intense emotional exertion, negative emotional state, but less severe effects of vibration were seen in orientative-trying reactions that are inborn, inherited forms of behaviour.

The article presents the results of experimental studies on the effects of noise on the body of white rats. That long-term exposure to noise (1, 4 months) leads to an increase in slow-wave activity, as well as changes in visual and auditory cortical response, with an increase in latency and a decrease in the amplitude values of the main peaks, indicating that the stress response of animals to the stimulus. Additionally, chronic exposure leads to noise reduction in general motor activity, increased anxiety, reduced emotional activity animals. Pathological examination revealed a violation of the vascular nature when exposed to noise for 15 days, longer duration of action of factor causes irreversible changes in the nervous tissue in the form of reduction in the total number of neurons per unit area, the presence of glial scarring in the area of 2 layers of the cerebral cortex, increasing the number of cells astroglia.

In the present study the criteria of the pathological process verification in the central nervous system of the albino rats induced by the long-term inhalation exposure to the metallic mercury vapors are presented. The theta-range was found to dominate which was replace for beta-range in the long-term period after exposure which was revealed at the early period of the examination in distributing the principal powers in background recording the electroencephalogram. (EEG) in the animals exposed to mercury vapors. This may testify the instability of the dominant rhythms. The beta 1and theta rhythms were found to dominate in the control animals during the both terms of the examination. The index of the deltaand beta 2-rhythms in the branches of the parietal and occipital of the heard as well as the indices of K 1, K 2, K 3 as the indices of the expression degree of the pathological changes in the ratio of the rhythm power of the bioelectrical brain activity were found to be the important differential criteria of the changes in EEG in the long-term period after mercury intoxication.

The article covers results of long-standing research on clinical peculiarities and course of toxic encephalopathy in distant period of occupational neurointoxications, on main concepts and pathogenetic steps of formation and progress of toxic encephalopathy. Through investigation covered firemen after exposure to complex of toxic chemicals and patients in post-contact period of chronic mercury intoxication. Modelling of chronic inhalation of metallic mercury vapors was performed.

The article deals with influence of longstanding inhalation of mercurial vapors on behavior of white rats, on morphologic and functional disorders in nervous system, on peculiarities of neuromediators metabolism in brain homogenate over the post-contact period.

The article covers problem of experimental biologic modelling of toxic encephalopathies. The authors represent major methodic approaches to modelling, criteria and methods to evaluate pathologic condition of CNS, present results of own research in creating models of toxic encephalopathies caused by metallic mercury and vinylchloride inhalation.

Prolonged inhalation of metallic mercury vapors by white rats appeared to result in toxic encephalopathy manifesting in disorders of orientative and investigatory, emotional behavior - increased anxiety, aggressiveness, negative e motionalism, higher locomotion activity. Throughout the experiment the animals had increased aggressiveness and muscular tone.

The results of determining the mercury levels in albino rat internal organs after inhalation exposure to metallic mercury vapour are presented in this paper. The significant differences in the mercury levels have been revealed in the rat mercury substrates studied of the experimental and control groups have been revealed after stopping the inhalation exposures as well as some time exposure. The alterations in emotional state with increase in aggressiveness were observed to be in the albino rats during the examination after stopping the inhalation exposure and 9 weeks after stopping mercury contact.