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Biomedical subjects

I I Poletaeva

Publications and source records attributed to I I Poletaeva.

At least 55 records · Page 3Linked to original sources

[The comparison of levels of anxiety and stress response in mice selected for low and high brain weight].

Emotionality, anxiety and stress reactivity were studied in mice selected for large (LW) and small (SW) brain weight. The open-field test, startle reaction, cross-maze, tail suspension and slippery funnel tests were used. It was shown that the SW mice are more active in the open field, more anxious and predisposed to the stereotyped behavior and passive reactions in stress situations. The relationship between the studied traits and brain weight and their influence on cognitive behavior are discussed.

Animals↗

[The genetics of behavior].

A review of the papers published in the Journal of Higher Nervous Activity dedicated to behavioral and neurophysiological studies carried out using the genetic approach is presented. The review is based on classification, which subdivides the diversity of behavioral phenomena into three large categories: instinctive, acquired behavior, and elementary reasoning phenomena. The main contribution to these publications was made by researches at the Institute of Cytology and Genetics, Russian Academy of Sciences, Siberian Branch (Novosibirsk), Institute of Physiology, Russian Academy of Sciences (St.-Petersburg), and Department of Physiology of Higher Nervous Activity, Biological Faculty, Lomonosov State University (Moscow). The traditional lines of investigations are: behavioral and neurochemical consequences of domestication, numerous physiological correlations in rat strains selected for high and low excitability levels, and genetic studies of animal reasoning.

Animals↗

[The effect of phenamine and caffeine on the ability to extrapolate in rats].

Solution of an extrapolation problem was studied on 28 albino rats (Way strain and laboratory population) and 68 hybrids (the first generation) of wild and laboratory rats in experiments with a screen--the search of food after the disappearance of the food stimulus from the animal's sight. Administration of caffeine (20 mg/kg) and d,l-amphetamine (0.1 mg/kg), though not changing the share of correct solutions, diminishes the number of "refusals" to solve it. Increased motor activity and diminished emotionality of the rats due to administration of the drugs, recorded in an open field test, are likely to cause a decrease in the number of refusals. Administration of d,l-amphetamine facilitates the process of conditioning which contributes to the greater number of positive solutions of the repeatedly presented task.

Amphetamine↗

[Structural abnormalities of hippocampus in 101/HY mice].

We studied cytoarchitectonics of the hippocampus in 101/HY and CBA mice on brain sections stained after Nissl and Timm. In CBA mice, the structure of hippocampus was normal. In 10/HY mice, stratum pyramidale in field CA3 was "splitted" and the density of pyramidal neurons was decreased. Abnormalities were also found in the zone of suprapyramidal projections of mossy fibers (sp-ME), i.e., terminals of axons of the fascia dentata granular cells on the apical dendrites of pyramids. If in CBA mice the sp-MF zone was normal, i.e., looked like a vast compact formation or dense ordered bundle, in 101/HY mice, the sp-MF zone represented a group of scattered, diffuse, and interrupted bundles of varying length, some of which were incorporated in stratum pyramidale. Possible causes of the described morphological abnormalities are discussed, as well as their relation to specific features of biology, behavior, and neurological status of 101/HY mice.

Animals↗

[Rapid tolerance to ethanol and high voluntary alcohol consumption in mice selected for brain weight].

Mice of two strains selected for small and large brain weight (SB and LB, respectively) had free access to 10% alcohol and water within three months. At the end of this period, they consumed alcohol in daily dose of 6.9 +/- 0.9 and 7.5 +/- 0.8 g/kg, respectively. After a period of imposed three-day abstinence, the alcohol consumption by the mice of these strains increased by 68.6 and 49.3%, respectively. Exploratory behavior of independent groups of mice from these strains was studied in the closed cross-maze. The animals were injected with ethanol (2.4 g/kg, i.p.) or vehicle twice with a weekly interval. In SB mice, the first ethanol administration increased the total time of maze exploration and the number of stereotyped visits. The second ethanol administration did not increase the time of exploration but increased the number of stereotyped visits even to the greater extent. The latter indicates the development of rapid tolerance and sensitization of these behaviors to the drug, respectively. The ethanol administration inhibited exploratory patrolling behavior and defecations. In LB mice, both the first and second ethanol administrations increased the number of stereotyped visits and decreased the exploration time and the number of defecations. The results do not support the psychomotor stimulant hypothesis of alcohol addiction. It is proposed that SB and LB mice may serve as models for Cloninger's types 1 and 2 alcoholics and may be useful for investigation of neuropharmacological mechanisms of stimulatory and inhibitory effects of ethanol.

Alcohol Drinking↗

[Behavioral and morphological asymmetry in brain weight selected mice].

Mice selected for large and small brain weight preferred to move rightwards in two cognitive paradigms, food-motivated T-maze performance and extrapolation ability tests. The degree of asymmetry in choices of movement direction varied in selection generations and sometimes was accompanied by asymmetry in the weight of the left and right hippocampi and other forebrain structures and different numbers of right and left neocortical cells.

Animals↗

[A factor analysis of behavioral organization in mice].

Laboratory mice with Robertsonian translocation Rb(8,17)1Iem, mice of CBA substrain with the same translocation as well as CBA normal karyotype mice were investigated in several behavioural tests, their results being analysed by means of factor analysis. The genetic differences were revealed in the patterns of factor loadings, in particular in factors "feeding behaviour structure" and "weight loss". The behaviour of mice during logic problem solving (the ability to extrapolate the direction of food stimulus movement was tested) proved to be genotype-dependent in respect to connections with exploratory behaviour indices. Tendencies towards stereotypic or variable (plastic) behaviour patterns were revealed in CBA mice and mice with Rb(8,17)1Iem mice respectively.

Animals↗

[Effect of neonatal influences on pain and audiogenic sensitivity and the content of monoamines in the adult rat brain].

In adult Wistar, KM, and Wag/Rij rats, the threshold of pain sensitivity (tail-flick test) and degree of spasm attack in response to a strong sound were estimated after neonatal administration of Semaks (analog of ACTG4-10 fragment) or after placebo (administration of saline for the control of the effect of neonatal pain stimulation). These neonatal influences did no affect the rates of sensorimotor maturation at an early age (Fox tests), i.e., did not affect directly the physiological activity of rat pups at the age of up to 21 days. In all control rats injected with saline (pain stimulation), the latent periods of audiogenic attacks increased reliably, while their degree decreased. Administration of Semaks "raised" these parameters to the lvl of those in intact animals, i.e., increased the sensitivity to sound. Neonatal administration (per os) of caffeine to KM rats increased reliably the latent period of audiogenic attacks. The thresholds of pain sensitivity in the rats of all strains were significantly lower than in the intact control, just as the level of dopamine in the hippocampus of KM rats. These data are interpreted as an evidence of changes in the development of some brain systems in response to neonatal influences.

Adrenocorticotropic Hormone↗

[The influence of neonatal ketamine injection on pain sensitivity and audiogenic seizures in adult rats].

The remote effects of neonatal (on the 3d-to-9th postnatal days) ketamine injections (10 and 50 mg/kg in 20 microliters of distilled water, s.c.) were analyzed in adult Wistar, WAG/Rij, and KM (a strain with high audiogenic sensitivity) rats. Both ketamine and water injections increased pain sensitivity in adult rats. Neonatally injected water increased the mean score of seizures in Wistar and WAG/Rij, whereas ketamine water solution injected in the dose of 50 mg/kg did not change the seizure intensity (as compared to the intact control). Consequently, ketamine significantly reduced the mean score of the audiogenic seizure fit without change in its latency. In highly sensitive KM rats the neonatally injected ketamine (50 mg/kg) significantly shortened the mean latency of the fit onset, and fit stages developed faster. Thus, the neonatal ketamine injection increased the audiogenic seizure susceptibility of brain structures in KM rats.

Acoustic Stimulation↗

[Neonatal Semax and saline injections induce open-field behavior changes in mice of different genotypes].

DBA/2, CBA mice, and their F1 hybrids (first series) and 101/HY and C3H mice (second series) were injected as neonates (2-7 days of life) with Semax (sc., 7 microg per animal). Semax is a peptide analogue of ACHT4-10 fragment which is resistant to degradation. The common feature of remote effects of both Semax and saline injections was the set of changes in the open-field behavior in adult (2.5- to 3-month-old) animals as compared to intact mice. Unexpectedly, the neonatal saline injections induced many changes in adult behavior, part of these effects being genotype-dependent. The most conspicuous shifts (genotype-dependent increase or decline) in freezing, grooming and rearing scores were displayed by DBA/2 and C3H mice, whereas the hole-poke frequencies were significantly changed in CBA and C3H mice. Squares crossed in the center of arena and rearing number were significantly increased in saline group of DBA/2 mice, whereas in Semax-injected DBA/2 group they were approximately equal to the level of intact mice. This means that the remote effects of noxious stimulation (injections of saline) were in some ways "compensated" as the result of concomitant peptide effect. At the same time, the numbers of freezing and grooming episodes were also increased in these groups. Because exploratory behavior and manifestations of anxiety increased or decreased simultaneously, it proves to be difficult to ascribe these changes to behavioral modulation along the "novelty seeking--anxiety" axis. In mice of other genotypes, changes in the same indices of the open-field behavior were revealed, but these changes were different in their direction. It was suggested that the complex patterns of postnatal behavior was the result of neonatal injections modulating subsequent brain development.

Adrenocorticotropic Hormone↗

[Remote effects of early postnatal pituitary hormone melatonin injection on audiogenic seizures in Krushinsky-Molodkina rats].

Rats Krushinsky-Molodkina inbred strain (KM) genetically prone to audiogenic seizures were injected with pineal hormone melatonin (50 mg/kg, s.c.) within the period 7th to the 14th posnatal days (PND). The remote effects of this injection adult KM rats consisted in a decrease in the latency and increase in severity of myoclonic seizures produced by audiogenic kindling (20 sound stimuli, 100 dB and 12-15 kHz). As compared to the control, in the cortex and hippocampus of rats of melatonin group, we also found a significant reduction of both total and functional activity of Ca2+/calmodulin-dependent protein kinase II (CAMK II) after audiogenic kindling. On the contrary, melatonin administration within the 1st to 7th PND and the 14th to the 21st PND resulted in a decrease in seizure activity. In the first case, both the total (cortical) and functional (hippocampal) CAMK II activities in melatonin-injected rats were increased as compared to control, whereas in the second case, only a slight increase in Ca2+-independent CAMK II activity in the hippocampus of melatonin-injected rats was observed. Probably, the melatonin administration in the period of early postnatal development changes the features of expression and/or regulation of CAMK II activity, and this could be one of the mechanisms of audiogenic seizure modulation in KM rats.

Animals↗

[The ability to extrapolate the direction of movement in mice selected for large and small brain weight: the influence of environmental enrichment].

Female mice from the strains selected for large and small brain weight (LB, SB) were kept either in "enriched" or in standard laboratory environment for 3 months. At the end of this period they were tested in the open field and for the ability to extrapolate the direction of the food stimulus movement. Scores of the LB mice kept in the "enriched" environment were significantly higher in the extrapolation test as compared to the LB mice kept in the standard environment as well as to the SB mice of both groups.

Animals↗

[Rats of Krushinsky-Molodkina strain: studies of audiogenic epilepsy, vascular pathology, and behavior].

Physiological, biochemical and genetic studies of audiogenic epilepsy in Krushinsky-Molodkina (KM) rat strain are analyzed. In brief, the history of KM strain selection and its current state are reviewed. Physiological mechanisms of the typical audiogenic seizure development and the audiogenic myoclonus (audiogenic kindling phenomena) are considered. The EEG correlates of these phenomena are presented. Biochemical features of the strain (neurotransmitter and neuronal membrane biochemistry) are described.

Acoustic Stimulation↗

[The effect of the ACTH(4-10) fragment on certain forms of adaptive behavior in mice of various genetic groups].

CBA/Lac/Sto mice, C57/BL/6J mice and random bred mice with robertsonian translocation of chromosomes 8 and 17 (T1IEM mice) were compared under normal conditions and after ACTH4-10 injections. The rate of food procuring learning in U-shaped maze and in radial 5-arm maze was studied, and the ability of mice to extrapolate the direction of stimulus movement. Peptide i. p. injections (40 mkg/kg) stimulated the learning in U-shaped maze in all genotypes. T1IEM mice demonstrated better radial arm maze performance than CBA. Peptide injections tended to improve it in the former and to impair in the latter genotype. T1IEM mice demonstrated the ability for extrapolation, while CBA mice revealed no such ability. ACTH4-10 injections improved problem solving only in T1IEM mice. Cases when animals "refused" to participate in the experiment, were significantly rare in groups of all genotypes under peptide treatment.

Adaptation, Physiological↗

[The level of noradrenaline and serotonin in mice differing in behavior].

Laboratory mice possessing Robertsonian translocation Rb (8, 17) 1IEM in their karyotype, reveal statistically significant ability for extrapolation of the direction of stimulus movement which disappears from animal's view. Inbred CBA mice with the same translocation are less capable, and CBA mice with normal karyotype are totally incapable of solving this task. Cortical noradrenaline levels in mice with Rb (8, 17) 1IEM were the lowest and brain stem levels the highest among the three groups investigated. Serotonin levels reveal no changes among these groups.

Animals↗

[Effect of amizil and the ACTH4-10 fragment on the ability of mice to extrapolate the direction of movement].

Mice possessing the ability to extrapolate the direction of movement (100% of correct choices) were injected i.p. with different doses of m-cholinolytic amizil 2 hours before experiment. Doses of 2-5 mg/kg reduced the percentage of correct choices, the adequate solving strategy being replaced by stereotyped unidirectional reactions or stereotyped alternating responses. Doses of 8-12 mg/kg induced "refusals" to solve extrapolation problem. When amizil treated mice were intraventricularly injected with 1 mg/kg of ACTH4-10, their extrapolation ability was restored. This compensatory action of peptide could be mediated by its influence on cholinergic as well as on other neurotransmitter systems.

Adrenocorticotropic Hormone↗

[Food search by mice solving an extrapolation problem after suppression of smell by zinc sulfate].

Anosmia induced by intranasal zinc administration to mice capable of solving an extrapolation problem (search for food which disappears from animal sight in definite direction), led to disturbance of normal food searching behaviour. In anosmic mice the percentage of task solutions (correct as well as incorrect) in which the trajectory was the shortest ("goal-directed"), was significantly lower than in controls. At the same time the percentages of correct "goal-directed" choices were equal in both groups. The main differences in the number of correct task solutions were among those trials in which non-goal-directed behaviour was delivered. Thus zinc induced anosmia provokes rather severe deteriorations of food searching behaviour. The investigated group of mice possessing Robertsonian translocation Rb(8, 17) 1 IEM, reveals no disturbance of extrapolation capacity during first 20 s after task presentation. This signifies that this capacity which in this group is higher than in other mice, is not determined by peculiarities of their olfaction.

Animals↗