Behavioural characterisation of young adult transgenic mice overexpressing galanin under the PDGF-B promoter

The behavioural phenotype of transgenic mice (3- to 5-months old) overexpressing galanin (GalOE) under the platelet-derived growth factor B (PDGF-B) promoter was evaluated in a battery of tests, including open field, locomotor cages, light-dark exploration test, elevated plus-maze and the Porsolt forced swim test. Learning and memory were assessed in the passive avoidance and the Morris water maze tasks. No difference between genotypes was found in exploratory activity in the open field. GalOE mice showed a slight increase in spontaneous locomotor activity assessed in the locomotor cages, but the amphetamine-induced increase in locomotor activity was somewhat lower in GalOE mice. Anxiety-like behaviour in the three different tests including open field, light-dark exploration and elevated plus-maze did not differ between genotypes. In the Porsolt forced swim test, GalOE mice displayed an increased time of immobility, indicative of increased learned helplessness possibly reflecting increased stress-susceptibility and/or depression-like behaviour. GalOE mice showed normal learning and memory retention in the passive avoidance and the Morris water maze tasks. These data support the hypothesis that galanin may have a role in functions related to mood states including affective disorders.     

Effects of bilateral electrolytic lesions of the medial nucleus accumbens on exploration and spatial learning.

Rats with electrolytic lesions of the medial part of the nucleus accumbens, comprising the shell region, were compared to sham-operated rats in tests of exploration in a T-maze, in a hole-board, and in an elevated (+)-maze and in a test of water maze spatial learning. Rats with medial nucleus accumbens lesions had higher choice latencies than sham-operated controls during the beginning of the spontaneous alternation test. A higher number of hole pokes was found in the lesioned group, but only during the beginning of the second day of testing. In the elevated (+)-maze, lesioned rats had a higher number of closed and total arm entries and spent more time in the center region. The lesioned group did not differ from the control group for the number of alternations in the T-maze, for horizontal and vertical motor activity in the hole-board, and for acquisition or reversal of spatial learning in the Morris water maze. These results indicate that lesions of the medial nucleus accumbens slowed down decision time during spontaneous alternation testing and increased exploration in a time and test-specific manner without altering acquisition of a reference memory task.     

Measuring Motor Coordination in Mice

Mice are increasingly being used in behavioral neuroscience, largely replacing rats as the behaviorist''s animal of choice. Before aspects of behavior such as emotionality or cognition can be assessed, however, it is vital to determine whether the motor capabilities of e.g. a mutant or lesioned mouse allow such an assessment. Performance on a maze task requiring strength and coordination, such as the Morris water maze, might well be impaired in a mouse by motor, rather than cognitive, impairments, so it is essential to selectively dissect the latter from the former. For example, sensorimotor impairments caused by NMDA antagonists have been shown to impair water maze performance². Motor coordination has traditionally been assessed in mice and rats by the rotarod test, in which the animal is placed on a horizontal rod that rotates about its long axis; the animal must walk forwards to remain upright and not fall off. Both set speed and accelerating versions of the rotarod are available.The other three tests described in this article (horizontal bar, static rods and parallel bars) all measure coordination on static apparatus. The horizontal bar also requires strength for adequate performance, particularly of the forelimbs as the mouse initially grips the bar just with the front paws. Adult rats do not perform well on tests such as the static rods and parallel bars (personal observations); they appear less well coordinated than mice. I have only tested male rats, however, and male mice seem generally less well coordinated than females. Mice appear to have a higher strength:weight ratio than rats; the Latin name, Mus musculus, seems entirely appropriate. The rotarod, the variations of the foot fault test¹² or the Catwalk (Noldus)¹⁵ apparatus are generally used to assess motor coordination in rats.     

Effects of angiotensin II and its receptor antagonists on motor activity and anxiety in rats.

The neuropeptide angiotensin II (Ang II) has been recently found to be involved in cognitive processes. Both AT1 and AT2 angiotensin receptors seem to mediate this action. However, unspecific behavioural effects of the peptide, particularly motor and emotional, appear to influence the interpretation of cognition-oriented tests and contribute to considerable differences in opinions of various authors on the subject. In this study, aimed specifically at the assessment of these effects, we found small and insignificant changes in motor performance measured in open field after intracebroventricular injections of Ang II and its receptor subtype-specific antagonists; losartan (AT1) and PD 123319 (AT2). However, Ang II was found to increase substantially anxiety measured in elevated 'plus' maze and impair motor coordination measured in 'chimney test'. Interestingly, both antagonists abolished Ang II generated anxiety and only losartan counteracted impaired motor coordination caused by the peptide. The AT2 receptor antagonist PD 123319 impairing motor coordination on its own, nonetheless partly diminished that caused by Ang II. Therefore it appears safe to conclude that mood but not motor effects of AT1 and AT2 receptor affecting drugs may significantly bias interpretation of the cognition-oriented tests on these drugs.     

Some behavioural effects of carbamazepine - comparison with haloperidol.

The experiments presented in this paper aimed to investigate the influence of atypical antiepileptic drug carbamazepine (CBZ, CAS 298-46-4) classified also as normothymic drug on spatial memory in Morris water maze test and anxiolytic effect in two-compartment exploratory test in rats. The study also investigated the probably occurring side effects (measuring cataleptic activity and motor coordination) following single and chronic administration of CBZ compared to haloperidol (HAL, CAS 52-86-8), a conventional antipsychotic. All the tests were carried out on male Wistar rats. CBZ 30 mg/kg was administered orally 60 min before the tests and HAL 0.15 mg/kg was administered orally 60 min before the tests. In the Morris test memory improvement only after chronic administration of CBZ on the 7 and 14 day of treatment was observed, whereas after 14 days of HAL treatment spatial memory impairment was noted. In the two-compartment exploratory test 30 mg/kg of CBZ had an anxiolytic effect after 7 and 14 days of treatment, whereas HAL did not show anxiolytic effect after single and chronic treatment. CBZ did not induce catalepsy after single as well as chronic administration. HAL evoked a strong cataleptic effect both after acute and chronic treatment. CBZ had no impact on motor coordination in the chimney test and HAL disturbed motor coordination in rats after single as well as chronic administration. CBZ may be an useful normothymic drug using in bipolar affective disorder treatment with co-occurred anxiety and cognitive deficits. The lack of significant side effects of CBZ may be an alternative way of treatment in comparison with older drugs, such as lithium carbonate.     

Long term neurological and behavioral effects of graded perinatal asphyxia in the rat

Perinatal hypoxic-ischemic states can cause irreversible damage to the brain, ranging from minimal brain dysfunction to death. Only few studies have been reported describing neurological, cognitive and behavioral deficits following perinatal asphyxia. We therefore decided to study long term effects of perinatal asphyxia in a well-documented animal model resembling the clinical situation. Caeserean section in rats was performed and the pups, still in the uterus horns, were placed into a water bath at 37 degrees C for periods of 5-20 min; pups were then given to surrogate mothers and examined at three month of age. Examinations consisted of a battery of motor and reflex tests, Morris water maze, multiple T-maze, elevated plus maze and open field studies. No abnormalities were found in rats even with long periods of perinatal asphyxia by neurological examination, in the open field and in mazes. Interestingly, in the elevated plus maze rats with long lasting exposure to hypoxia (15 and 20 min of asphyxia) showed reduced anxiety-related behavior. This finding may be relevant for the explanation of anxiety related disorders in adulthood with a tentative history in the perinatal period.     

Lifelong Caloric Restriction Increases Working Memory in Mice

Caloric restriction (CR) is argued to positively affect general health, longevity and the normally occurring age-related reduction of cognition. This issue is well examined, but most studies investigated the effect of short-term periods of CR. Herein, 4 weeks old female mice were fed caloric restricted for 4, 20 and especially for 74 weeks. CR mice received 60% of food eaten by their ad libitum (AL) fed littermates, and all age-matched groups were behaviorally analyzed. The motor coordination, which was tested by rotarod/accelerod, decreased age-related, but was not influenced by the different periods of CR. In contrast, the age-related impairment of spontaneous locomotor activity and anxiety, both being evaluated by open field and by elevated plus maze test, was found aggravated by a lifelong CR. Measurement of cognitive performance with morris water maze showed that the working memory decreased age-related in AL mice, while a lifelong CR caused a better cognitive performance and resulted in a significantly better spatial memory upon 74 weeks CR feeding. However, a late-onset CR feeding in 66 weeks old mice did not ameliorate the working memory. Therefore, a lifelong CR seems to be necessary to improve working memory.     

Effect of circadian phase on performance of rats in the Morris water maze task

The authors examined spatial working memory in the Morris water maze during the activity and rest periods of Wistar rats. Wheel-running activity was measured continuously as a marker of circadian phase. To minimize possible masking effects on performance, animals were placed in constant dim light the day before testing and tested in similar light conditions. Three experiments were run, each of them using animals varying in their previous experience in the water maze. Half of the animals of each experiment were tested 2 to 3 h after activity onset (active group), and the other half were tested 14 to 15 h after activity onset (inactive group). In the three experiments, a significant phase effect was observed in the animals' performance in the water maze; animals tested in the active phase showed steeper acquisition curves. These phase effects on performance are due to the animals' search pattern and not to a better acquisition and maintenance of spatial information; rats tested in the inactive phase found the platform faster on the first trial of the test, when the information on the location of the platform had not been presented to the animals. This effect vanished as the amount of training in the pool increased. Finally, swimming speed also showed a temporal effect, suggesting the existence of a phase effect for motivation to escape from the water; rats tested during their inactive phase tended to swim faster. All together, the data suggest a modulating effect of the biological clock on performance in the water maze, particularly when the animals are less experienced.     

The effect of motor abilities on karate performance

The aim of the study was to identify the motor structures that determine achievement of top results in karate. The study included a sample of 85 karateka aged 18-29 years, competing as senior category athletes of the Croatian Karate Society. Fourteen motor tests (9 basic motor tests and 5 specific motor tests) were used to assess technical efficiency; fighting efficiency was estimated on the basis of results achieved at a number of contests. Factorial analysis of the basic set of motor variables indicated the presence of three major factors of coordination, explosive strength, and movement frequency. Factorial analysis of pooled basic and specific motor variables also pointed to three major factors of speed (basic and specific), controlled power (explosive strength and specific agility), and basic coordination. Regression analysis showed the isolated basic factors to significantly determine both technical and fighting efficiency of the karateka, with the major role of the factor of explosive strength (power). Regression analysis of pooled basic and specific factors revealed the factors of controlled speed and controlled power to predominantly determine the karateka fighting and technical efficiency. In the set of tests used to assess specific motor abilities in karate, the speed of blockade, the speed of moving in multiple directions, and frequency of foot kicking were found to be the best predictors of technical efficiency, whereas the speed of moving in multiple directions, the speed of blockade, and frequency of foot kicking were the best predictors of fighting efficiency.     

Behavioral effects of prenatal folate deficiency in mice

BACKGROUND: Folate supplementation decreases the incidence of birth defects such as neural tube defects (NTDs). We and others have shown that gestational dietary folate deficiency that does not produce overt NTDs can alter fetal neural histology. Accordingly, murine offspring were examined for the possible functional consequences of prenatal folate deficiency. METHODS: CD-1 mice were fed a diet of chow containing 400, 600, or 1200 nmol of folic acid/kg of chow for eight weeks prior to breeding and until GD18, at which time all dams were placed on folate-replete chow. Behavioral tests of male and female offspring included righting reflex, negative geotaxis, forelimb hanging, motor coordination, open field activity, and elevated plus maze activity. RESULTS: Of greatest significance, the adult offspring that were prenatally folate-deficient exhibited more anxiety-related behavior in the elevated plus maze. Offspring of the 400 nmol of folic acid/kg of chow diet group exhibited significantly shorter durations in the open arms and longer durations in the closed arms. Further, these two behaviors were dose-related. There was also a trend for the prenatally folate-deficient adult mice to exhibit more thigmotaxis (wall-hugging) behavior in the open field, entering the central area less frequently than controls. There were few other differences in tested behaviors between folate-deficient and folate-replete mice. CONCLUSIONS: Prenatal folate deficiency that is repleted at birth can manifest later with increased anxiety 9-12 weeks after birth.     

Repeated treatment with cholecystokinin octapeptide improves maze performance in aged Fischer 344 rats.

Previous studies have shown that sulfated cholecystokinin octapeptide (CCK-8S) can improve learning in adult rodents when administered systemically or into the central nucleus of amygdala. Here we analyzed the effect of repeated intraperitoneal (i.p.) injection of CCK-8S on the performance of 26-month-old Fischer 344 rats in different versions of the Morris water maze and in a rota-rod test of motor coordination. Old rats were injected daily with different doses of CCK-8S (0.32 to 8.0 microg/kg; IP) 10 min before the behavioral tests. Control groups included vehicle-injected old and adult (3-month-old) F 344 rats. To control for a possible development of tolerance to the behavioral effects of repeated CCK-8S administration, groups of aged rats were included which were subjected to an acute rather than a repeated CCK injection schedule. The repeated administration of CCK-8S did not influence the performance of the old rats in the hidden-platform version of the maze. In addition, the acute treatment with CCK-8S failed to modify navigation performance in this task, suggesting that drug-tolerance may not account for the lack of behavioral effects seen after repeated CCK-8S injection. During the "probe trial", the percentage of animals per group, which swam exactly across the former platform site, was markedly increased in aged rats treated repeatedly with 1.6 microg/kg CCK-8S. This might be indicative of improved retention of the prior platform location and/or a higher resistance of the learned escape response to extinction. The specificity of the effect of CCK-8S on processes related to spatial learning and memory is supported by the lack of effect on motor performance.     

Dihydrotestosterone modulates spatial working-memory performance in male mice

Androgens affect cognitive processes in both humans and animals. The effects of androgens may be limited to certain cognitive domains, specifically spatial memory, but this hypothesis remains elusive. Here, we tested castrated and sham-operated mice in various behavioral tasks to ask whether androgens affect multiple or specific cognitive domains in male mice. Castration impaired spatial working memory performance in the delayed matching to place water maze task following a 1-h, but not a 1-min, retention interval, as has been reported for rats. In contrast, castration had no effect on novel object recognition memory, spatial reference memory in the water maze, motor coordination, or passive avoidance memory. Castration increased anxiety-like behavior in the open field test, but not the elevated zero maze. Finally, we assessed the effects of androgen replacement with non-aromatizable dihydrotestosterone on spatial working memory following various retention intervals. Dihydrotestosterone recovered spatial memory performance following a 24-h, but not a 1-h retention interval, and had no effect at other retention intervals. These data support that in male mice androgens specifically affect spatial working memory performance, and that the neurobiological processes underlying spatial memory formation may be differentially affected by androgens.     

Fetal hydantoin syndrome in rats: dose-effect relationships of prenatal phenytoin on postnatal development and behavior

Sprague-Dawley rats were gavaged once daily on days 7-18 of gestation with, 100, 150, or 200 mg/kg of phenytoin. Only the highest dose of phenytoin decreased maternal weight during gestation or increased offspring mortality up to weaning. Offspring were evaluated for activity prior to weaning (pivoting and photocell) and afterwards (figure 8, open-field, and hole-board), dynamic righting development, maze learning (Biel maze), and visual discrimination (Y maze), and for startle reaction to both auditory and tactile stimuli. The highest dose of phenytoin produced increased activity on all tests of activity, delayed dynamic righting development, impaired Biel maze and Y-maze learning, and inhibited tactile startle responses. The two lower doses of phenytoin generally showed a dose-effect relationship with values on most measures intermediate between values for controls and for the highest-dose group. Dose-effect relationships were most evident on measures of early activity (both tests), dynamic righting, and Biel maze learning, whereas only trends were evident on measures of later activity, Y maze, and startle. A dose-related rotational defect was found in a minority of phenytoin offspring, and although these individuals contributed to the behavioral abnormalities observed, they in no instance accounted for the overall pattern of effects seen in the phenytoin offspring. Maternal plasma phenytoin levels at the end of treatment were dose-related. Offspring showed no effects on postnatal growth, total brain weight, or brain protein content as adults. The data support the view that phenytoin is a potent behavioral teratogen at doses well below those causing any evidence of gross teratogenicity or embryotoxicity.     

The impact of basic motor abilities on the specific motoricity performance in elite karateka

The aim of the study was to identify motor structures that determine high performance in karate. The study included a group of 85 karateka aged 18-29 years, competing as senior category athletes within the Croatian Karate Society. A battery of 22 motor tests (9 basic motoricity tests and 13 specific motoricity tests) were used. Factor analysis of the basic motor variables pointed to the existence of three significant factors: coordination, explosive strength and movement frequency; whereas factor analysis of the specific motoricity area indicated two significant factors, i.e., factor of technical efficiency and factor of specific agility. Canonical correlation analysis showed the isolated set of basic motor factors to significantly determine both technical efficiency and specific agility-mobility of the karateka, with a predominance of the explosive strength (force) factor, followed by the speed and coordination factors.     

Strength training for 1h in humans: effect on the motor performance of normal upper extremities

It has been found that one session of intense muscle strength training decreases muscle strength temporarily and causes neuromuscular fatigue in the trained muscles, but little attention has been given to the effects of neuromuscular fatigue on the other components of motor performance. The purpose of this study was to examine in normal healthy volunteers the effects of a 1-h strength training session on the motor performance of the upper extremity, including reaction time, speed of movement, tapping speed and coordination. Group of 30 healthy female volunteers, aged 29-47 years, were randomly divided into sub-groups, (A and B, n = 15 per group). Both groups first completed a set of motor performance tests on 3 consecutive days. On the 4th day, group A carried out a 1-h muscle strength training session of the upper extremities. Isometric muscle strengths and electromyogram (EMG) data were recorded before the training session. Immediately after the training session the same recordings were repeated, and additional motor performance tests were also performed. Group B carried out only the motor performance tests. The groups exchanged programmes the following week. The 1-h strength training session decreased the isometric muscle strength of wrist flexion by 18% (P < 0.001) and extension by 18% (P < 0.001) in group A, while in group B flexion strength decreased by 19% (P < 0.001) and extension strength by 17% (P < 0.001). All the measured EMG activations also decreased in both groups. There were no statistically significant differences in the results of the motor performance tests between the mean values of the three baseline measurements and the values recorded after the training session. The result was surprising, but straightforward; neuromuscular fatigue induced by a 1-h strength training session of the upper extremities had no effect on the motor performance functions of the hand, as indicated by reaction times, speed of movement, tapping speed and coordination, in these normal healthy female volunteers.     

Characterizing spatial extinction in an abbreviated version of the Barnes maze

Adult male Wistar rats were trained to find an escape box in the Barnes maze in order to characterize the extinction process of a learned spatial preference. To do so, once they had fully acquired the spatial task, they were repeatedly exposed to the maze without the escape box. Multiple behavioral measurements (grouped into motor skill and spatial preference indicators) were followed up throughout the complete training process. Animals gained efficiency in finding the escape box during acquisition, as indicated by the reduction in the time spent escaping from the maze, the number of errors, the length of the traveled path, and by the increase in exploration accuracy and execution speed. When their retention and preference were tested 24 h later, all the subjects retained their enhanced performance efficiency and accuracy and displayed a clear-cut preference for the escape hole and its adjacent holes. Almost all motor skill indicators followed an inverse, though not monotonic, pattern during the extinction training, returning to basal levels after three trials without escape box, displaying a transient relapse during the fifth extinction trial. Preference indicators also followed a reverse pattern; however, it took seven trials for them to return to basal levels, relapsing during the eighth extinction trial. The abbreviated Barnes maze acquisition, evaluation, and extinction procedures described herein are useful tools for evaluating the effects of behavioral and/or pharmacological treatment on different stages of spatial memory, and could also be used for studying the neurophysiological and neurobiological underpinnings of this kind of memory.     

Neurotoxicity of fluoride: neurodegeneration in hippocampus of female mice

Light microscopic study of hippocampal sub-regions demonstrated significant number of degenerated nerve cell bodies in the CA3, CA4 and dentate gyrus(Dg) areas of sodium fluoride administered adult female mice. Ultrastructural studies revealed neurodegenrative characteristics like involution of cell membranes, swelling of mitochondria, clumping of chromatin material etc, can be observed in cell bodies of CA3, CA4 and dentate gyrus (Dg). Fluoride intoxicated animals also performed poorly in motor co-ordination tests and maze tests. Inability to perform well increased with higher fluoride concentration in drinking water.     

Evaluation of social and physical enrichment in modulation of behavioural phenotype in C57BL/6J female mice

Housing conditions represent an important environmental variable playing a critical role in the assessment of mouse behaviour. In the present study the effects of isolation and nesting material on the behaviour of female C57BL/6J mice were evaluated. The mice were subjected to different rearing conditions from weaning (at the age of 3 weeks). The study groups were group- and single-housed mice, divided further into groups with or without nesting material (species-specific enrichment). After 8 weeks spent in respective conditions the behavioural testing began. Both factors (social conditions and nesting material) appeared to have a significant impact on the behavioural phenotype. However, it is important to stress that the interaction between the factors was virtually absent. We established that isolation increased locomotor activity and reduced anxiety-like behaviour in several tests of exploration. In contrast, absence of nesting material increased anxiety-like behaviour. Neither factor affected rota-rod performance, nociception and prepulse inhibition. Contextual fear memory was significantly reduced in single-housed mice, and interestingly, in mice with nesting material. Cued fear memory was reduced by single-housing, but not affected by enrichment. Mice from enriched cages displayed faster and better learning and spatial search strategy in the water maze. In contrast, isolation caused significant impairment in the water maze. In conclusion, both isolation and species-specific enrichment have profound effects on mouse behaviour and should be considered in design of the experiments and in assessment of animal welfare issues.     

QTL analysis identifies multiple behavioral dimensions in ethological tests of anxiety in laboratory mice

BACKGROUND: Ethological tests of anxiety-related behaviors, such as the open field arena and elevated plus maze, are often carried out on transgenic animals in the attempt to correlate gene function with a behavioral phenotype. However, the interpretation of such tests is problematic, as it is probable that different tests measure different aspects of behavior; indeed, anxiety may not be a unitary phenomenon. Here, we address these questions by asking whether behaviors in five ethological tests of anxiety are under the influence of a common set of genes. RESULTS: Using over 1600 F2 intercross animals, we demonstrate that separate, but overlapping, genetic effects can be detected that influence different behavioral dimensions in the open field, elevated plus maze, square maze, light-dark box, and mirror chamber. We find quantitative trait loci (QTLs) on chromosomes 1, 4, and 15 that operate in four tests of anxiety but can be differentiated by their action on behavior in threatening and nonthreatening environments and by whether habituation of the animals to an aversive environment alters their influence. QTLs on chromosomes 7, 12, 14, 18, and X influenced a subset of behavioral measures. CONCLUSIONS: The chromosome 15 QTL acts primarily on avoidance behavior, the chromosome 1 QTL influences exploration, and the QTL on chromosome 4 influences activity. However, the effects of loci on other chromosomes are not so readily reconciled with our current understanding of the psychology of anxiety. Genetic effects on behaviors in these tests are more complex than expected and may not reflect an influence on anxiety.     

Stability in Activity and Boldness Across Time and Context in Captive Siberian Dwarf Hamsters

Individual personality is an important source of variation in animal behavior. However, few studies have examined the reliability of individual behaviors across both time and context for even common temperament traits such as boldness, especially in mammals. We tested a laboratory colony of Siberian dwarf hamsters (Phodopus sungorus) in two similar assays, a tunnel maze and an open field, both provisioned with a home nestbox for shelter. Animals were tested in each assay at three ages, beginning at weaning. Principal components analysis on each assay identified an axis of activity level in both tests, boldness and reactivity in the tunnel maze, and nestbox orientation in the open field. All traits were moderately (7–18%) heritable. Individual activity level was the most reliably consistent trait, both within and between tests. Tunnel maze boldness, tunnel maze reactivity, and open field nestbox orientation did not correlate at any age. Correlation between boldness and activity changes from positive to negative as animals age, while reactivity was consistently negatively associated with activity. A negative correlation emerged in adults between open field activity and nestbox orientation. These results suggest that either development or habituation results in different personality trait associations in an individual over time. Individual temperament traits such as general activity level may be quite stable, but caution should be used in generalizing single assays to represent boldness across time and across contexts.