Correlated variability in motor activity and emotionality in selecting rats for high and low values of active avoidance conditioned reflexes

The open-field behaviour of rats selected for high and low active avoidance level was studied. The data obtained showed the correlated response of two selected lines for avoidance ability with the locomotor activity and emotional reactivity in the open-field situation. The line of a low avoidance value had the low activity level and high defecation score in comparison to the alternative one and to progenitory Krushinsky--Molodkina strain. The correspondence of learning ability and emotionality-motivation performance has been discussed.     

Features of the behavior of the rat with hereditarily determined arterial hypertension

The behaviour of spontaneously hypertensive rats (SHR strain), rats with inherited stress induced arterial hypertension (ISIAH, a new developed strain), and of their normotensive Wistar progenitors was studied. The open-field arena and a device for measuring the total activity in the home cage were used in the behavioural studies. The SHR were much more active in the open--field and home cage tests than the Wistar and ISIAH rats. The basal locomotor activity of the ISIAH strain was lower than that of the Wistar rats, but the ISIAH strain had an index of behavioural reactivity 2.7 fold higher than the Wistar or SHR strains. These behavioural characteristics corresponded to the hypertension patterns of the strains compared. Enhanced spontaneous locomotion of the SHR rats was associated with spontaneous increase in arterial blood pressure. The ISIAH rats showed low spontaneous locomotor activity, but high behavioural and blood pressure reactivity under conditions of mild emotional stress.     

Genetically determined variability in rat behavior and its biochemical correlates

Using the combination of extremely high and low values of two independent behavioural variables (activity and frequency of defecation in open field) four groups of rats were selected with different CNS reactivity corresponding to the types of higher nervous activity described by I.P. Pavlov. These groups of rats revealed significant differences in reactivity to stress and drugs, in social behaviour and biochemical pattern. They may represent a useful tool for the research in experimental psychology, neurophysiology, psychopharmacology and other branches of science.     

The respiration and oxidative phosphorylation of the brain mitochondria in rats with different types of behavior]

Respiration and oxidative phosphorylation of brain mitochondria were studied in outbred rats with different types of behaviour in open-field test and in forced swimming test. It was found that in rats with "active" type of behaviour (with high locomotor activity and low level of depressiveness) the brain mitochondria have at succinate oxidation a higher rate of respiration in active metabolic state and in presence of uncoupler 2,4-DNP, and a higher rate of ADP phosphorylation than in rats with "passive" type of behaviour (with low locomotor activity and high and moderate levels of depressiveness). Thus rats with active type of behaviour have a higher succinate oxidase activity than rats with passive type of behaviour. It is supposed that revealed differences in brain energy metabolism may affect the dominance of certain type of behaviour.     

The characteristics of the synchronizing action of melatonin on the dynamics of circadian mobility in rats

Morning (9.00-10.00 h), but not noon, repeated injections of the pineal hormone melatonin (1 or 10 mg/kg daily, during 2 weeks) synchronize the circadian locomotor rhythm of rats. As shown with inverted photoperiod, melatonin facilitates off and on light reactions. Some animals have low and some high hormonal susceptibility. This indicates the role of injections regime and rat's individual reactivity for expressiveness of melatonin synchronizing effect.     

Chronopharmacologic characteristics of the development of tolerance for the narcotic effect of ethanol in a hot climate

The experiments have been carried out on rats tested by Parsolt in various time of the day in January and July. The results of investigations showed that the behaviour activity of animals was exposed to daily and season fluctuations. The tolerance development to the ethanol narcotic effect depends upon the behaviour activity of animals. During summer the increasing of ethanol toxicity was observed. In highly active rats as distinct from low active animals the real increasing of noradrenaline concentration and the decreasing of dofamine concentration were noted. Ethanol changes the correlations of blood monoamines and the behaviour activity of animals.     

Ability to Maintain Internal Arousal and Motivation Modulates Brain Responses to Emotions

Persistence (PS) is defined as the ability to generate and maintain arousal and motivation internally in the absence of immediate external reward. Low PS individuals tend to become discouraged when expectations are not rapidly fulfilled. The goal of this study was to investigate whether individual differences in PS influence the recruitment of brain regions involved in emotional processing and regulation. In a functional MRI study, 35 subjects judged the emotional intensity of displayed pictures. When processing negative pictures, low PS (vs. high PS) subjects showed higher amygdala and right orbito-frontal cortex (OFC) activity but lower left OFC activity. This dissociation in OFC activity suggests greater prefrontal cortical asymmetry for approach/avoidance motivation, suggesting an avoidance response to aversive stimuli in low PS. For positive or neutral stimuli, low PS subjects showed lower activity in the amygdala, striatum, and hippocampus. These results suggest that low PS may involve an imbalance in processing distinct emotional inputs, with greater reactivity to aversive information in regions involved in avoidance behaviour (amygdala, OFC) and dampened response to positive and neutral stimuli across circuits subserving motivated behaviour (striatum, hippocampus, amygdala). Low PS affective style was associated with depression vulnerability. These findings in non-depressed subjects point to a neural mechanism whereby some individuals are more likely to show systematic negative emotional biases, as frequently observed in depression. The assessment of these individual differences, including those that may cause vulnerability to depressive disorders, would therefore constitute a promising approach to risk assessment for depression.     

Genetical aspects of hormonal modification of the stress reactivity. II. Modification in early ontogenesis of the stress reactivity of adult gray rats selected for behavior toward man

Inherited and modificational changes of the stress reactivity in two outbreed stocks of wild Norway rats trapped in nature and selected for behaviour were studied. During 18 generations the rats of one stock were selected for the lack of defensive behaviour in the glove test (tame), while in another stock the aggressiveness was maintained by the selection (aggressive). Interstock differences in the brain noradrenaline mechanisms were observed. The emotional stress reactivity of the tame animals was decreased, in comparison with the aggressive ones. Definitive stress reactivity of adult rats was modified by injections of hydrocortisone to their mothers on the 16 and 18 days of gestation. Hormonal treatment changed noradrenaline mechanisms and decreased the reaction to emotional stressor in aggressive rats. The modified level of the stress reactivity of aggressive rats was similar to the definitive level of the tame ones. Hormonal treatment did not modify stress reactivity in tame rats. Thus, the phenotype only emerging in aggressive rats, as a result of hormonal modification, is the inherited norm of the tame animals. However, due to rat selection for the lack of defensive behaviour towards the man, high corticosteroid level in the blood of pregnant females, an external developmental factor, in respect to the fetus, loses regulatory function during the development of the neuroendocrine mechanisms of the stress reaction.     

Chemical characterization of porcine blood serum components with A and SLA activity

The porcine A blood group substance is found in the serum as a Lipid and, additionally, in certain animals, as a glycoprotein. Swine lymphocyte antigens (SLA) occur in the serum only as glycoproteins. Heat treatment of the solid residue obtained by lipid extraction yielded a water-soluble fraction with low protein content, high A activity, but no SLA activity. Poly(glycosy1)ceramides with SLA activity do not occur in the serum; poly(glycosy1)ceramides with A activity cannot be excluded. Desialylation of protein fractions has no effect on A and SLA activity. Both A and SLA activities of protein fractions are stable to mild alkaline hydrolysis thus indicating N-glycosidic carbohydrate-peptide linkages.     

The dynamic behavioral changes in rats after destruction of the locus coeruleus]

Destruction of locus coeruleus (LC) was conducted in adult rats (male rats of the Wistar line, 250-300 g) electrolytically or by means of 6-hydroxydopamine (6-OHDA). Behaviour of the intact animals sham-operated and of rats with destructed LC was evaluated before and every week after the operation during 5 weeks. Statistically significant alterations in the behaviour were revealed only in the initially low-active rats. These animals were characterized firstly, by low motor and exploratory activity in all tests (open field and automated devices), disturbance of the reactivity to novelty--only in one week after the operation with subsequent compensation of shifts; secondly, by low level of investigatory activity in the open field and absence of habituation to the repetitive tests--from the 21-st day after the operation.     

Reactivity of brain benzodiazepine receptors and individual sensitivity of rats to pentylenetetrazole

The individual sensitivity of the male Wistar rats to acute pentylenetetrazole injection was studied, the density and the affinity of benzodiazepine receptors in the cerebellar cortex for 3H-diazepam was measured. It was demonstrated that the reactivity of benzodiazepine receptors underlies the individual sensitivity to pentylenetetrazole. The animals with higher sensitivity were characterized by more intensive reaction than the control and resistant animals, i.e., by an decrease in the receptors density (the initial receptors density being equal in the sensitive, resistant, and control animals). Daily injections of a subconvulsive dose of pentylenetetrazole during 24 days increase the animal sensitivity to this substance, and this was accompanied by an increase in the reactivity of benzodiasepine receptors. Later on, the produced high sensitivity became somewhat lower but persisted for 6 months. The receptors density in this period reduced almost by half. In sensitive rats, a single low dose of pentylenetetrazole injected 6 months after treatment increased the density of benzodiazepine receptors. The age-matched controls, the same acute dose of pentylenetetrazole decreased both the receptor density and affinity of their binding. It is suggested that the increase in reactivity of benzodiazepine receptors is actualized via the intracellular metabotropic feedback mechanism.     

Type of behavior and superoxide dismutase activity in the brain of rats (a comparison of 2 Tryon strains)

Differences in the type of behaviour in capable ("maze-bright") and incapable ("maze-dull") Tryon rats have been demonstrated in the situation with pain-irritated partner by the method of "emotional resonance". Most "bright" rats belonged to the type not avoiding the signals of another pain-irritated rat, they revealed a persistent ecologically defensive reaction of preferring a small closed space. The type of anxiety behaviour prevailed in the group of "dull" rats. In the open field test "bright" rats were characterized by low locomotor activity and high level of defecation and "dull" rats by high activity and low defecation. Increased levels of superoxide dismutase activity and high content of thiobarbituric acid-reactive material were observed in brains of dull rats. The interrelations between behavioural and molecular levels of defensive response to stress is discussed.     

The presence of blood group and lymphocyte antigens on porcine granulocytes

Suspensions of highly viable (< 95 %) granulocytes minimally contaminated by other cell types were isolated from the peripheral blood of pigs by a single centrifu-gation with low molecular weight dextran and after preferential lysis of erythrocytes by hypotonic shock. A complement-dependent cytotoxic test showed the presence of antigens of the SLA major histocompatibility complex, the SLB leucocyte system and the A and E blood group systems on the granulocytes. Some SLA typing reagents against class I (SD) antigens did not react with granulocytes, however, or yielded dubious reactions. The findings showed that the reactivity of SLA sera resembles the reactivity of human HLA sera. The results also show that compatibility in the SLA, SLB, A and E systems will have to be taken into account when preparing alloimmune sera for the determination of granulocyte-specific antigens of pigs.     

Criteria of individual variations in the reactivity of the respiratory system

Individual variations of the respiratory system reactivity have been studied in experiments on rats. It is shown expedient to estimate reactivity of the respiratory system to hypoxic hypoxia by the pattern of changes in the total oxygen uptake. Animals demonstrating no essential changes in the oxygen uptake in response to hypoxia (11% O2) are referred to individuals with high reactivity of the respiratory system; those responding by a drastic decrease in the oxygen uptake--to animals with low reactivity of the respiratory system. A strong correlation is determined between the respiratory system reactivity and individual resistance of organism to acute hypoxic hypoxia.     

Correlation of the behavioral characteristics of animals with varying levels of alcohol motivation: motor activity, taste and electrical pain sensitivities

It is shown that rats with a high degree of orienting-investigatory behaviour, low thresholds of emotional and pain sensitivity consume considerably more ethanol and rejected substances--urea and mustard--in comparison with low-active, less electrical pain-sensitive animals with a low degree of alcohol motivation. It is suggested that studying of characteristics of specialized appetite can be an important factor for prognostication of behaviour and role of individual in population.     

Adaptive behavior of active and passive rats after intranasal administration of the corticotropin-releasing hormone

Behavioural effect of intranasal application of corticotropin-releasing hormone (CRH) was investigated in rats with high (KHA) and low (KLA) rate of learning in "open field" and plus-maze (PM) active avoidance test. The neurohormone provoked the opposed changes in behaviour of rats of this strain in both tests. The level of locomotion and exploratory activity rose in KLA rats and decreased in KHA rats. After the CRH application, the KLA rats but not KHA rats spent more time in the opened alleys of the PM than the control animals. The same behavioural changes were observed in our previous research when CRH was injected in striatum. We suppose that CRH is an endogenous factor of precise correction of the adaptive behaviour.     

Effects of dietary changes on muricide activity in adult and young rats

Recent works have showed different interrelations between dietary tryptophan intake and aggressive behaviour in different groups of rats. In this experiment the AA. have treated thirty Sprague-Dawley rats (15 youngs and 15 adults) with tryptophan free-diet, during eight weeks. Muricide activity was weekly controlled; daily food intake for all group was recorded. Young rats feeding tryptophan free-diet and young rats pairfed controls showed aggressive behaviour at the sixth week of treatment. Adult rats did not show any changes of mouse killing during the whole period of experiment.     

Contribution to histochemical distribution of non-specific cholinesterase activity in sensory ganglia of some mammals

The activity of non-specific cholinesterase was demonstrated histochemically in satellite cells of the spinal ganglia from adult rat, cat, rabbit and baboon. The spinal ganglia of newborn rats displayed distinct intraneuronal reactivity for non-specific cholinesterase while a low reactivity was observed in satellite cells. The spinal and trigeminal ganglia of adult mice contained satellite cells with non-specific cholinesterase reactivity only sporadically. Most of reaction product for non-specific cholinesterase activity (from low to high intensity) was found in perikarya of the neurons. Spinal and trigeminal ganglia of the same mice embryo exhibited diffuse staining for non-specific cholinesterase activity remaining in the spinal ganglia of newborn mice. The trigeminal ganglia of newborn mice exhibited, however, more differentiated pattern of the positive reaction for non-specific cholinesterase like adult animals. The pattern of histochemical distribution of non-specific cholinesterase activity in trigeminal and spinal ganglia from mice of various ages corresponds with morphological differentiation and maturation undergoing in a rostrocaudal wave. Intraneuronal presence of non-specific cholinesterase activity in sensory ganglia during development and in adult animals gives a new possibilities for explanation of the functional involvement of this enzyme in the nervous system.     

Comparison of video recording and a portable electronic device for measuring the feeding behaviour of individually housed dairy goats

A detailed knowledge of chewing behaviour is important in understanding the factors that can affect digestive function in high producing ruminants. The aim of this study was to compare chewing behaviour either measured with a portable automatic system (APEC) which records jaw movements or obtained by scan sampling video analysis in 12 individually housed dairy goats. One hour and daily time-intervals were used for the analysis. APEC and video showed better agreement for 1 h than for daily time-intervals but a very high individual variability was observed for all the parameters measured. Daily duration of rumination seemed to be assessed better by the APEC than by the video because it is sometimes difficult to determine if the goats are resting or ruminating on the video. Daily duration of intake was however assessed better by the video because the automatic recorder interpreted all oral behaviours as intake. However, total chewing time is directly related to the amount of saliva produced which an important factor in ruminant nutrition. The APEC allows continuous recording of activity independently of the animal's position in the pen or in a group or at pasture where animals cannot be filmed, however the device can be easily damaged by the animals. Video cannot be damaged by the animals but it can be difficult to determine the animal's activity if the animal is lying-down or not facing the camera, or in a dark part of its pen. Both systems were relevant to measure chewing behaviour of stall housed dairy goats, and to study the daily time-budget of feeding behaviour but results have to be interpreted carefully.     

Antagonism between L-DOPA and apomorphine in their effects on rat behavior

The effect of simultaneous injections of apomorphine and l-DOPA on stereotypy, aggressiveness, on the exploratory motor activity, the threshold of emotional reactivity and aggressiveness elicited by painful electrical stimulation was studied in experiments on male albino rats. When injected separately, in control experiments, both compounds had similar effects on the exploratory-motor activity and the emotional behaviour, but when injected simultaneously in various doses a distinct antagonism between l-DOPA and apomorphine, according to all the behaviour tests, was noted (a decrease of sterotypy, aggressiveness and emotional reactivity). Against the background of l-DOPA apomorphine (5 mg/kg) increased the dopamine content in the forebrain and in the diencephalon even more. It is suggested that the increased level of the functionally active mediator suppressed the activity of postsynaptic receptors sensitive to it.