The dynamics of the rats higher nervous activity disturbances after total influence of electrons and gamma-rays in doses 5-100 Gy

The dynamics of using of stabilized motor defensive conditioned reflex of active avoidance in "shuttle-box" in rats after total influence of high energy electrons and of gamma-rays in doses 5-100 Gy were investigated. The quality structure of higher nervous activity disturbances after the influence of these kinds of ionizing radiation was identical. Therefore the tendency to disturbances aggravating after the electron radiation influence in the periods of the initial depression and of relatively normalization was revealed, especially after the irradiation in dose 50 Gy. The effective compensation of the functional disturbances in the central nervous system at the first 5-10 min after irradiation was after influence of electron radiation in doses about 30 Gy and after the influence of gamma-radiation in doses about 50 Gy. The irradiation of rats in doses 10 Gy and 5 Gy caused qualitative different dynamics of radiation disturbances in rats higher nervous activity. The differences in rats higher nervous activity after influence of electron and of gamma-radiation in these doses did not manifest distinctly.     

Peculiarities of modifying influence of the factors forming the functional status of the central nervous system on dynamics of the rat higher nervous activity disturbances totally exposed to electron and gamma-radiation at a dose of 100 Gy

The dynamics of using a stabilized motor defensive conditioned reflex of active avoidance in "shuttle-box" in rats after the total influence of high energy electrons and gamma-rays at a dose of 100 Gy and a modifying influence of the two most important factors forming the functional status of the central nervous system: the stage of the conditioned reflex consolidation and typological peculiarities of the higher nervous activity have been investigated. The influence of both types of ionizing radiation has been shown to cause far more profound disturbances of non consolidated conditioned reflexes in comparison with the automatized conditioned reflexes and provoke an inverted picture of disturbances in the animals with opposed peculiarities of the higher nervous activity. The qualitative picture of the dynamics of disturbances that are caused by these types of radiation is identical. In summary, the studied conditions that form the functional status of the central nervous system determine the nature of neuroradiation syndrome to a greater extent than differences in the effectiveness of these types of radiation.     

Behavioural medicine in health promotion

Behavioural medicine is a rapidly developing interdisciplinary field that integrates the physiological and psychosocial aspects of human behaviour and applies them to prevention. In the early stage of chronic non-infectious illnesses of great epidemiological significance the most important risk factors are the reversible psychophysiological regulation disturbances. According to the behavioural medicine model depressive symptomatology, hopelessness, anxiety, non-adaptive ways of coping, dysfunctional attitudes are common risk factors in the background of self-destructive behavioural disturbances, such as smoking, alcohol and drug abuse and suicidal behaviour. The basic link between physiological and psychological phenomena is the decision making process, the cognitive appraisal, evaluation of the given situation, which is very subjective and depends on the socialization process. The modern civilised way of life continuously creates situations in which we experience loss of control, and therefore the psychological and physiological balance can only be obtained with great difficulty. Especially under conditions of sudden cultural and socioeconomic transition strengthening adaptive ways of coping and preventing emotional disturbances are fundamental in health promotion.     

The effective dosage as the stimulating exposure in fractionated gamma irradiation

The study of early neurological disturbances (END) in rats after fractionated gamma irradiation with doses of 37.5-225 Gy at dose rate of 30.11 Gy/min has demonstrated that the initial response of animals to pulse ionizing radiation is a function of the electric charge induced by ionizing radiation. A change in the probability of occurrence of each of the END symptoms, with the increased intervals between exposures, is merely an indirect indication of the eliminating mechanisms and is intricately connected with the irritating charge value. The period of dose half-elimination in 16 min. The threshold effective dose rate leading to END is of the order of 2.12 Gy/min. The proposed empiric relationships permit to correlate the probability of END symptom occurrence with the continuous quantitative parameter of fractionated irradiation, that is, with an effective dose as an analogue of the irritating effect.     

Psychophysiological development of two generations of female rats chronically exposed to gamma-irradiation during pregnancy in the total dose of 1 Gy and its modification by melanin

The purpose of the work was to study the embryotoxic action of chronic gamma-irradiation of pregnant female rats (F0) during the first 10 days of pregnancy in the total dose of 1 Gy (mean dose rate of 5.31 mGy/hour) on psychophysiological development of posterity of the first (F1) and the second (F2) generations and its modification by natural pigment melanin (peroral 10 mg/kg once per day during the irradiation). 54 pregnant female Wistar rats were the objects of research were their 180 descendants of the first generation and about 400 descendants of the second generation of maternal and of paternal lines. Psychophysiological development and its correction by melanin estimated on ability to learning with the test of training a conditioned avoidance reflex in the shuttle box. Precise negative action of gamma-irradiation in the aforesaid dose on psychophysiological development of posterity of the first generation is established. At rats of the second generation the inferiority is shown mainly at descendants of maternal line. Application of melanin of natural origin in most cases diminished negative consequences of the irradiation.     

The characteristics of higher nervous activity and of the brain benzodiazepine system in rats subjected to ethanol exposure in the prenatal period

Exposure to ethanol during pregnancy results in the alternation of 3H-diazepam binding to synaptosomal neocortical membranes from the rat offspring. In male experimental rats, 14 days of age, binding level diminished to 11%. In two-month-old control rats Scatchard plot was biphasic. It has been shown that prenatal exposure to ethanol leads to changes in the nature of binding in two-month-age experimental animals, as compared with the control ones. 3H-diazepam binding changes went along with behavioural deviations. In experimental rats locomotor activity was increased in the "open field" test, passive avoidance conditioned reflex retention was decreased and elaboration parameters of active avoidance conditioned reflex were changed, as compared with the control ones. The data obtained show that higher integrative functions were disturbed by prenatal alcoholization. Correlations between benzodiazepine receptor state and behaviour were studied.     

The characteristics of a change in the congenital and acquired forms of behavior in rats with genetic catalepsy

In two groups of rats--outbred control rats and GC line ones the behaviour in the open field was studied, as well as alimentary situational instrumental conditioned reflex was elaborated. Rats of GC line were less mobile in the open field as compared with the control ones; their investigating reflex was low; several parameters showed a higher level of agitation and fear. Handling of rats of GC line improves these behavioural parameters and brings them closer to the norm. Elaboration of alimentary situational conditioned reflex in rats of GC line is delayed as compared with the control ones. Passive-defensive reflex expressed in the form of cataleptic stupor, is of dominant character and significantly prevails over cognitive and alimentary reflexes.     

Effect of thymalin on protein synthesis in the brain and conditioned-reflex activity of the progeny of neurosensitized female rats

Thymalin administration to two-week-old offspring of neurosensitized female rats prevented the development of protein synthesis disturbances in the central nervous system and the retention of conditioned reflex of passive avoidance. Thymalin injection to the offspring of intact female rats improved conditioned reflex retention and did not affect brain protein synthesis. A possible mechanism of thymalin effect in conditions of congenital neuroimmunopathology is discussed.     

Effect of neurotizing exposures on conditioned reflex activity in the late postresuscitation period in rats

In white rats resuscitated after 10-minutes stop of the blood circulation, conditioned switching over was elaborated on the basis of alimentary and defensive instrumental reflexes and the effect was studied of neurotizing influences. Single application of electrocutaneous pain stimulus in alimentary situation ("collision") led to more expressed disturbances of conditioned activity in resuscitated rats than in intact ones. Differentiation of a signal different from the positive conditioned stimulus only by the height of the tone, was practically not elaborated in resuscitated rats, and the disturbance of the conditioned alimentary reflex to the reinforced signal appearing during differentiation elaboration, was manifest in them to a greater degree. The obtained data testify that even a short-time brain ischemia, accompanied by a fast and full restoration of the neurological status, leads to functional defects of the CNS appearing at subsequent neurotic influences.     

Radiation resistance of motor-defensive conditioned reflexes in rats at different stages of the formation and stabilization of a temporary connection

Disturbances were studied of the motor defensive conditioned reflexes in rats radiated in a dose of 100 Gy at different stages of formation and stabilization of temporary connection. In comparison with consolidated (automatized) conditioned reflexes of active avoidance, early stages of formation and stabilization of the temporary connection are characterized by a relatively low resistance against extreme factors and by deepest disturbances of reproduction in radiated animals. The most probable mechanisms of these disturbances are connected with pathological changes of the nervous processes balance towards an increase of excitability and weakening of internal inhibition. Yet a direct radiation influence on the mechanisms of temporary connection reproduction at the second stage of its consolidation cannot be excluded. The role is shown of the emotional reactivity in the above-described processes.     

Piracetam correction of deficient GABA-ergic inhibition due to early postnatal exposure to cycloheximide

Cycloheximide, administered to 7-day-old rats, caused the delay of CNS activity changes in grown-up rats. The animals showed impaired memory function, expressed in the decrease of habituation in the "open field" test, and the alteration of passive avoidance reflex. The increased number of intersignal reactions due to hypermotility was found during elaboration of avoidance reflex. The analysis of evoked potential recovery revealed the deficiency of GABA-ergic inhibition in the neocortex. Piracetam was shown to prevent completely behavioural disturbances and deficiency of GABA-ergic processes in grown-up animals.     

Characteristics of the function of the higher portions of the central nervous system of rats subjected to acute hypoxia in the antenatal period]

A reduction of motor activity, and of the orientative reflex, its more rapid extinction in comparison with control were seen in the sexually mature rats which sustained acute hypoxia during the antenatal period. The experimental animals displayed disturbances of the conditioned reflex activity indicating a worse fixation of the temporary association, weakening of the inhibitory process and reduction of the nervous process mobility. Epileptiform convulsions occurred in presentation of "difficult" experimental tasks. There was also noted an increase in convulsioness after the administration of threshold doses of carasol.     

Effect of adaptation to central highlands conditions on active avoidance conditioning and its retention after emotional pain stress

The generation of conditioned reflex of active avoidance (CRAA) and its retention after emotional stress were studied in different groups of rats. The degree of conditioned reflex of active avoidance in pre-adapted rats was higher than in non-adapted animals. However, the degree of CRAA maintenance was independent of the character of CRAA fixation and the rats' adaptability after 1 and 3 exposures to emotional stress. In a usual degree of conditioned reflex fixation its maintenance was higher in rats living on the plain than in low-mountain rats (adapted and non-adapted).     

Bystander and delayed effects after fractionated radiation exposure

Human immortalized keratinocytes were exposed to a range of single or fractionated doses of gamma rays from (60)Co, to medium harvested from donor cells exposed to these protocols, or to a combination of radiation and irradiated cell conditioned medium (ICCM). The surviving fractions after direct irradiation or exposure to ICCM were determined using a clonogenic assay. The results show that medium harvested from cultures receiving fractionated irradiation gave lower "recovery factors" than direct fractionated irradiation, where normal split-dose recovery occurred. The recovery factor is defined here as the surviving fraction of the cells receiving two doses (direct or ICCM) separated by an interval of 2 h divided by the surviving fraction of cells receiving the same dose in one exposure. After treatment with ICCM, the recovery factors were less than 1 over a range of total doses from 5 mGy-5 Gy. Varying the time between doses from 10 min to 180 min did not alter the effect of ICCM, suggesting that two exposures to ICCM are more toxic than one irrespective of the dose used to generate the response. In certain protocols using mixtures of direct irradiation and ICCM, it was possible to eliminate the bystander effect. If bystander factors are produced in vivo, then they may reduce the sparing effect of the dose fractionation.     

Favourable effect of physical exercise on informational pathology of higher nervous activity

As a model of neurotic states induced by information overload experimental neurotic states were evoked in 13 dogs reared under conditions of partial social isolation by shortening the intertrial intervals in an alimentary conditioned reflex situation with delayed reinforcement. Both behavioural and autonomous disturbances were completely abolished in 4 of 5 dogs which were systematically exposed to muscular activity. Similar protective and therapeutic effect had the muscular exercise which formed a main component of the therapy in 59 neurotic subjects.     

Probability analysis of elements of rat behavior after sudden and signalled interruption of food reinforcement

Probability analysis was carried out of the appearance of single elements of rats behaviour in the process of extinction of a conditioned alimentary motor reflex. The dynamics of effector behavioural components at a sudden cessation of reinforcement (usual schedule of extinction) was compared with cessation of reinforcement signalled by a previously differentiated signal and with reinforcement cessation preceded by a stimulus initially unknown to the animal. If the reinforcement cessation is signalled by a previously differentiated (negative) stimulus, in response to its action the animals "loose the aim", what is revealed in a rapid complete reduction of all elements of the goal-directed alimentary behaviour. Obviously differentiation signal actualises the memory trace of "nonreinforcement" which was formed in the previous negative experience of the animal; this is revealed in accelerated inhibition of the alimentary motor reflex under extinction.     

The influence of ZnCl2 injected into the neostriatum on locomotor behavior of rats

The influence of two-week daily microinjections of ZnCl2 into the rostral region of neostriatum on the locomotor behavior of Wistar rats in chronic experiments was studied. The 1-mcg dose of ZnCl2 decreased spontaneous locomotor activity in the "open field" and, beginning with the 5th day of microinjections, inhibited a shuttle-box conditioned avoidance reflex. The reflex recovered only in the first week after the injection withdrawal. The 0.1-mcg dose of ZnCl2 to a lesser extent affected the parameters of conditioned avoidance, whereas the level of spontaneous locomotor activity in this group of animals increased. The observed changes in rat behavior may be associated with the concentration-dependent influence of zinc ions on the ion channels in the membranes of neostriatum neurons, including glutamate activated. The possibility to control the activity of ion channels in a chronic behavioral experiment by zinc ion concentration is discussed.     

Prediction of the severity of damage and disruption of work ability in reaction of the body to alcohol load prior to radiation exposure in the superlethal range

In experiments on 121 white non-linear rats, 44 Papio hamadryas and 29 Macaca fascicularis, animals' reactions on the alcohol impact (AI) and following exposure to supralethal doses were compared. The animals were intravenously injected with 5% ethanol in the glucose solution, 2.1 g/kg for rats and 0.46-0.51 g/kg for monkeys. Monkeys' response to AI was scored in four-point scale by estimating of abnormalities in motor activity, coordination of motion and changes in conditioned reflex activity. It was shown that changes in the ability of alcohol-injected rats to perform the learnt exercises in the "jump box" could be used for prediction of their response to the exposure to supralethal doses of ionizing radiation. Observing the AI-response in monkeys along with a method "function of spying for moving object" made possible to predict not only a general degree of loss of working ability but also to estimate individual impairments of spying functions. In 65% monkeys high similarity of the reactions to AI and ionizing radiation was observed.     

The brain phospholipids following the irradiation of animals at a high dosage

In experiments with albino mice, rats and guinea pigs the effect of ionizing radiation (100 Gy) on brain phospholipids and their fatty acids has been investigated. Upon the development of manifest behavioural disturbances (2 h after irradiation) phospholipid molecules degrade insignificantly. Some changes in the relative content of phospholipids and their fatty acids are mainly found in the rat synaptosomal fraction: this may be responsible for the disturbances in the sensitivity of the receptor apparatus of cell membranes.     

Influence of neurotensin on behavior of rats with lesions in serotonergic neurons

After serotonergic lesion by administration of 5,7-dihydroxytryptamine into the dorsalis raphe nucleus, effects of neurotensin microinjections into the caudate nucleus and substantia nigra on rat behavior were compared. Serotonergic lesions resulted in motivated excitement of rats manifested as an increase in the number of intersignal motor reactions during realization and, particularly, extinction of thirst conditioned reflex. Neurotensin microinjections into the caudate nucleus facilitated extinction of the conditioned reflex both in operated and control rats, but such microinjection into the substantia nigra facilitated this process only in operated animals. Neurotensin did not change conditioned reflex realization in both groups of animals but decreased emotional excitement of rats in the "open field". The behavioral effects of neurotensin in operated rats are connected with normalization of motivational and emotional states of animals and may be explained by recovery of interaction between the dopamine- and serotonergic systems. It is suggested that the mechanisms of this normalizing effects of neurotensin at the levels of the caudate nucleus and substantia nigra are different and are associated preferentially with its action either on dopamine- or serotonergic structures.