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Behavioural and EEG changes induced by the pyrethroid insecticide cyhalothrin
441
In the present work, several principles and methodical approaches are proposed which may fulfil the above demands and which delineate an interdisciplinary field, termed in the present work, Medical Psychophysiology. Medical Psychophysiology is concerned with: - the effect of psychosocial stimuli upon physiologic functions; - higher nervous regulations of physiologic (especially autonomic) functions subserving the interaction of an individual with the (especially social) environment; - physiological mechanisms mediating the impact of certain psychological and social factors upon the human organism; - interaction of psychosocial, psychophysiological, and biological factors in the development and course of diseases; - application of psychophysiologically oriented methods to the treatment and prevention of diseases. In Medical Psychophysiology, epidemiological, experimental (in animal and man), and clinical methods are used. As an illustration of a psychophysiological approach from the above point of view, factors intervening in the response of a human organisms to psychosocial stress are discussed. Several results are presented of the author’s studies of the relationship between the ability to cope with actually experienced stressful situations in the premorbid life and the development of certain somatic diseases.
BEHAVIOURAL AND EEG CHANGES INDUCED BY THE PYRETHROID INSECTICIDE CYHALOTHRIN L. Zufan, J. Kubat, J. Formanek, A. Fuchs, and G. Tobl’Skova, P. Zajzek, J. Vodickovii, P. Rehak, J. Dvofak Institute of Hygiene and Epidemiology, Centre of Industrial Hygiene and Occupational Diseases, Research Group on Occupational Physiology, Occupational Psychology and Ergonomics Srobarova 48, 100 42 Prague 10, Czechoslovakia The wide use of insecticides mainly in agriculture
(plant protection) calls for new reliable and more effective compounds with low toxicity for mammals. The synthetic pyrethroids are a relatively new group. Some pyrethroid insecticides, synthetic analogues of natural pyrethrins, meet these needs. Their characteristics and effects are described by many authors and so far only some findings on their influence on the nervous system of mammals was published (Vijverberg, Bercken 1982, Dtsi et al. 1985). The principal effect of pyrethroius on the vertebrate nervous system is to induce repetitive activity, particularly in the sensory nervous system. There are differences in neurotoxic activity between the various pyrethroids, especially between a-cyano and noncyano compounds. The a-cyano derivatives cause profuse salivation and writhing or choreoathetotic movements of trunk and limbs (Type II). The noncyano pyrethroids which include natural pyrethrins and synthetic compounds (Type I) produce tremor and prostration without the pronounced writhing component of Type II compounds (Staatz, Hosko 1985). We have studied the influence of a new pyrethroid insecticide cyhalothrin (PP 321, trade mark Karate, chemically (S)-a-cyano-3-phenoxybenzyl (lR)-cis-3(2-2-chloro-3,3,3-fluoroprop-l-enyl)-2,2-dimethylcyclopropane-carboxylate) on the cortical EEC in rats. Cyhalothrin was administered both by the oral and peritoneal route in several doses from 25 mg/kg to 200 mg/kg as emulsion in solvents and surface active agents (concentrations 5% or 40%, respectively). The two-lead EEC of freely-moving rats was simuhaneously recorded on paper and magnetic tape recorders. Subsequently the recorded EEG was analyzed by means of an analogue broad-band frequency analyzer using a computer system which measured and evaluated time courses of the means of absolute values in individual bands. Automatic artefact detection and their replacement (two specialized programs) was used. The consecutive descriptive and comparative statistical methods made it possible to plot surveys of the results in user-friendly figures. The preliminary results reveal the changes in amplitudes (depression in majority of cases), in frequency composition (relative increase of beta activity) and in repetition of cycles of high and low amplitudes. The adapted open-field behavioral method has proved limited mobility as a consequence of discoordination of limbs in exposed animals. Some respiratory
448 difficulties, tremor, salivation, piloerection, increased reactivity to noise and during handling with vocalization were also observed. References D&i, I., Dobronyi, I. and Varga, L. 1985 Immuno-, neuro-, and general toxicologic animal studies on a synthetic pyrethroid : cypermethrin. Ecotoxicol. Environment. Safety 12: 220-232.
Staatz, Ch. G. and Hosko, M. 1985 Effect of pyrethroid insecticides on EEC activity in conscious, immobilized rats. Pest. Biochem. Physiol. 24: 231-239. Vijverberg, H.P.M. and van den Bercken, J. 1982 Action of pyrethroid insecticides on the vertebrate nervous system. Neuropath. appl. Neurobiol. 8: 421440.
In the present work, several principles and methodical approaches are proposed which may fulfil the above demands and which delineate an interdisciplinary field, termed in the present work, Medical Psychophysiology. Medical Psychophysiology is concerned with: - the effect of psychosocial stimuli upon physiologic functions; - higher nervous regulations of physiologic (especially autonomic) functions subserving the interaction of an individual with the (especially social) environment; - physiological mechanisms mediating the impact of certain psychological and social factors upon the human organism; - interaction of psychosocial, psychophysiological, and biological factors in the development and course of diseases; - application of psychophysiologically oriented methods to the treatment and prevention of diseases. In Medical Psychophysiology, epidemiological, experimental (in animal and man), and clinical methods are used. As an illustration of a psychophysiological approach from the above point of view, factors intervening in the response of a human organisms to psychosocial stress are discussed. Several results are presented of the author’s studies of the relationship between the ability to cope with actually experienced stressful situations in the premorbid life and the development of certain somatic diseases.
BEHAVIOURAL AND EEG CHANGES INDUCED BY THE PYRETHROID INSECTICIDE CYHALOTHRIN L. Zufan, J. Kubat, J. Formanek, A. Fuchs, and G. Tobl’Skova, P. Zajzek, J. Vodickovii, P. Rehak, J. Dvofak Institute of Hygiene and Epidemiology, Centre of Industrial Hygiene and Occupational Diseases, Research Group on Occupational Physiology, Occupational Psychology and Ergonomics Srobarova 48, 100 42 Prague 10, Czechoslovakia The wide use of insecticides mainly in agriculture
(plant protection) calls for new reliable and more effective compounds with low toxicity for mammals. The synthetic pyrethroids are a relatively new group. Some pyrethroid insecticides, synthetic analogues of natural pyrethrins, meet these needs. Their characteristics and effects are described by many authors and so far only some findings on their influence on the nervous system of mammals was published (Vijverberg, Bercken 1982, Dtsi et al. 1985). The principal effect of pyrethroius on the vertebrate nervous system is to induce repetitive activity, particularly in the sensory nervous system. There are differences in neurotoxic activity between the various pyrethroids, especially between a-cyano and noncyano compounds. The a-cyano derivatives cause profuse salivation and writhing or choreoathetotic movements of trunk and limbs (Type II). The noncyano pyrethroids which include natural pyrethrins and synthetic compounds (Type I) produce tremor and prostration without the pronounced writhing component of Type II compounds (Staatz, Hosko 1985). We have studied the influence of a new pyrethroid insecticide cyhalothrin (PP 321, trade mark Karate, chemically (S)-a-cyano-3-phenoxybenzyl (lR)-cis-3(2-2-chloro-3,3,3-fluoroprop-l-enyl)-2,2-dimethylcyclopropane-carboxylate) on the cortical EEC in rats. Cyhalothrin was administered both by the oral and peritoneal route in several doses from 25 mg/kg to 200 mg/kg as emulsion in solvents and surface active agents (concentrations 5% or 40%, respectively). The two-lead EEC of freely-moving rats was simuhaneously recorded on paper and magnetic tape recorders. Subsequently the recorded EEG was analyzed by means of an analogue broad-band frequency analyzer using a computer system which measured and evaluated time courses of the means of absolute values in individual bands. Automatic artefact detection and their replacement (two specialized programs) was used. The consecutive descriptive and comparative statistical methods made it possible to plot surveys of the results in user-friendly figures. The preliminary results reveal the changes in amplitudes (depression in majority of cases), in frequency composition (relative increase of beta activity) and in repetition of cycles of high and low amplitudes. The adapted open-field behavioral method has proved limited mobility as a consequence of discoordination of limbs in exposed animals. Some respiratory
448 difficulties, tremor, salivation, piloerection, increased reactivity to noise and during handling with vocalization were also observed. References D&i, I., Dobronyi, I. and Varga, L. 1985 Immuno-, neuro-, and general toxicologic animal studies on a synthetic pyrethroid : cypermethrin. Ecotoxicol. Environment. Safety 12: 220-232.
Staatz, Ch. G. and Hosko, M. 1985 Effect of pyrethroid insecticides on EEC activity in conscious, immobilized rats. Pest. Biochem. Physiol. 24: 231-239. Vijverberg, H.P.M. and van den Bercken, J. 1982 Action of pyrethroid insecticides on the vertebrate nervous system. Neuropath. appl. Neurobiol. 8: 421440.