[Interhemisphere neurochemical differences in the brain of silver foxes selected for behavior and the problem of directed asymmetry]. / Mezhpolusharnye neirokhimicheskie razlichiia mozga u serebristo-chernykh lisits pri otbore po povedeniiu i problema napravlennoi asimmetrii.

The study deals with the mechanisms that bring about a directional asymmetry in the expression of some morphological traits observed in some animals subjected to experimental domestication. The key role in the integration of development is attributed to the genetic systems controlling the activity of brain neurotransmitter systems. Therefore, the investigation of directional asymmetry of morphological traits began with the analysis of interhemispheral differences in neurotransmitter activity in animal lines selected for domestic and aggressive behavior. Experiments on silver foxes reveal interhemispheral differences in the dopaminergic system emerging in the striatum. An increased dopamine level is observed in the right half of the striatum of aggressive foxes and in both right and left halves of the striata of domestic foxes. On the basis of the literature data, it is suggested that the considerable increase in the dopamine level in the right halves of the striata of both aggressive and domestic animals is related to a genetic increase in the manifestation of emotional response in both lines, whereas its increase in the left half of the striatum of domesticated foxes may be related to a correlated deterioration of the function of the pituitary-adrenal system.

[Selection vector and ontogenetic development of behavior under domestication of wild Norway rats]. / Vektor otbora i ontogeneticheskie zakonomernosti formirovaniia povedeniia pri deomestikatsii serykh krys.

Hereditary variation in rates of ontogenetic formation of exploratory behavior, glucocorticoid functions, and neurotransmitter systems in wild Norway rats during selection for absence of defensive response towards humans (domestication) is demonstrated. Interrelated shifts in the development of behavior and neurohormonal systems are shown. A comparison of the data obtained with the results of domestication of another species-silver fox-suggests that equally vectorized selection of animals belonging to different taxa produces equally directed changes of their regulatory systems.

[The circadian dynamics of the biochemical activity of the epiphysis in silver foxes]. / Sutochnaia dinamika biokhimicheskoi aktivnosti épifiza serebristo-chernykh lisits.

Specific features of light-dependent biosynthesis of melatonin in the epiphysis are analyzed in female silver-black foxes. Just as in most previously studied animals, the serotonin and 5-hydroxyindolylacetic acid content of epiphysis decreased during the dark time of the 24 h period, while the activity of the melatonin-synthesizing enzyme N-acetyltransferase and melatonin content of epiphysis and plasma, on the contrary, markedly and reliably increased. However, the pattern of changes in the neurotransmitters dopamine and noradrenaline shows specific features.

[The interaction of GABA-A receptors with the serotoninergic system of the brain in regulating the testosterone level by the negative feedback mechanism]. / Vzaimodeistvie GAMK-A retseptorov s serotinergicheskoi sistemoi golovnogo mozga v reguliatsii urovnia testosterona mekhanizmom otritsatel'noi obratnoi sviazi.

A unilateral hemicastration decreased the serotonin and 5-hydroxyindolacetic acid levels in the Wistar rat mediobasal hypothalamus, but not in the midbrain. These neurotransmitters were shown to interact in the process of androgen restoration after the hemicastration. The maximal contribution of GABAergic mechanisms in the testosterone feedback regulation involves the GABA effect via the central GABA-A receptors of the mediobasal hypothalamus' serotoninergic neurons, thus activating the hormone level restoration. The GABA seems to induce a serotonin-independent inhibition of the testosterone level stabilising after hemicastration.

[Monoamine oxidase activity in the brain of male laboratory mice differing in the capacity for social dominance]. / Aktivnost' monoaminoksidaz v golovnom mozge samtsov laboratornykh myshei, otlichaiushchikhsia po sposobnosti k dominirovaniiu.

The activity of type A and B monoamine oxidases (MAO-A and MAO-B) was studied in the brain stem and cerebral hemispheres of male mice from the PT and CBA inbred laboratory lines with opposite dominance capabilities and in their direct and reciprocal F1 hybrids. MAO-B activity was shown to be lower in the hemispheres of intact PT males and F1 hybrid males, which are genetically predisposed to social domination, than in CBA males. One-hour social stress imposed by grouping mice into a micropopulation resulted in a decrease in MAO-A and MAO-B activity in the hemispheres of dominant PT and F1 hybrid males and an increase in MAO-B activity in the brain stem of subordinant CBA and dominant F1 males.

[Catecholamine levels and tyrosine hydroxylase activity in the brain structures of male mice with a determined behavioral type in a population]. / Urovni katekholaminov i aktivnost' tirozingidroksilazy v strukturakh golovnogo mozga samtsov myshei s determinirovannym tipom povedeniia v populiatsii.

Biosynthetic activity in brain catecholaminergic neurons was studied in male mice with genetically determined dominant (PT strain) and subordinate (CBA) behaviour. The dominant PT mice were characterized by higher levels of catecholamines and tyrosine hydroxylase activity in most of the brain regions in comparison with subordinate CBA mice. Percent of animals with dominant type of behaviour was high among the hybrid F1 males derived from PT and CBA mice. These offsprings inherited also the high levels of noradrenaline and dopamine as well as the high tyrosine hydroxylase activity in the striatum and the brain stem. The obtained data suggest that the level of biosynthetic activity in the brain catecholaminergic neurons is essential for coordination of the brain neurochemical systems in expression of the dominant male mice behaviour in a population.

[The relationship between catecholamine levels, tyrosine hydroxylase activity in the brain and the rank of male mice in a population hierarchy]. / Zavisimost' mezhdu urovniami katekholaminov, aktivnost'iu tirozingidroksilazy v golovnom mozge i rangom samtsov myshei v populiatsionnoi ierarkhii.

This study was aimed to investigate processes of biosynthesis in catecholaminergic system of male mice with genotypically determined dominant and submissive behaviour in population and their F1 offsprings. F1 inherited not only high capacity for dominance but also high tyrosine hydroxylase activity and catecholamine levels in striatum and hindbrain. It has been concluded that the high level of biosynthesis in catecholaminergic neurons is necessary for coordination of neurochemical systems involved in the regulation of genotypically determined dominant behaviour in male mice.

[Neurochemical correlates of dominant behavior in mice]. / Neirokhimicheskie korreliaty dominantnogo povedeniia u myshei.

The influence of genetic factors on the activity of a key catecholamine-synthesizing enzyme and the relationship between the synthesis parameters in catecholaminergic systems and the predisposition of male mice of inbred lines to dominate in a population were studied. It was determined that the interline variability of tyrosine hydroxylase activity in the cortex, hippocampus, hypothalamus, striatum, and hindbrain exceeded the intraline one. PT line and CBA/Lac males were characterized respectively by maximum and minimum enzymatic activity in the majority of brain regions and also by dominant and subordinate behavior determined by genotype. Significant rank interline correlations of noradrenaline levels in the striatum, hippocampus and hindbrain, tyrosine hydroxylase activity in the striatum and hindbrain, and the percentage of dominant males among the examined genotypes were found. It was concluded that a genetically determined relationship exists between biosynthetic processes in the noradrenergic neurons of the brain and a dominant behavior phenotype.

[The participation of adrenoreceptors in regulating dominant behavior and gonadal endocrine function in male mice of different genotypes]. / Uchastie adrenoretseptorov v reguliatsii dominantnogo povedeniia i éndokrinnoi funktsii gonad u samtsov myshei raznykh genotipov.

Dominant behaviour and testosterone level were investigated after adrenoreceptor (AR) blocking drugs injections in PT and CBA/Lac mice predisposed, correspondingly, to dominant and subordinate behaviour in a population and their hybrids F1. Phentolamine (alpha-AR blocker, 1 mg/kg) or obsidan (beta-AR blocker, 1 mg/kg) injections resulted in a loss of the dominant rank of CBA/Lac mice and did not affect the PT mice behaviour. Higher doses (2 and 5 mg/kg) were also ineffective. Simultaneous phentolamine and obsidan injections (1 mg/kg) caused a dominant phenotype inversion, decrease of aggression and testosterone level in PT mice. F1 inherited an ability to dominate in a population and a sensitivity of AR form PT inbred strain. Their behaviour and endocrine characteristics after injections of AR-blockers were close to those of PT mice.

[Tyrosine hydroxylase activity and expression of its gene in mice with contrasting capacity to dominate in social stress]. / Aktivnost' tirozingidroksilazy i ékspressiia ee gena u kontrastnykh po sposobnosti k dominirovaniiu myshei pri sotsial'nom stresse.

Changes of tyrosine hydroxylase (TH) activity and level of mRNA of TH gene in PT and CBA/Lac mouse strains, which are contrast by ability to dominate in heterogenous populations, were investigated. It was established, that the activity of TH both in dominate PT and subordinate CBA/Lac mice in hypothalamus, hippocampus and brain stem elevated in one hour after forming of micropopulations. But the appearance of this increase was different: activation of TH in hypothalamus and brain stem of PT mice was stronger then one in CBA/Lac mice. Moreover, the beginning of the reaction in brain stem of PT mice was earlier then that of CBA/Lac mice. MRNA level of TH gene in hypothalamus and brain stem in one hour was elevated only in PT mice for 50% and 200%, respectively. No changing in expression TH gene was found in hippocampus. In conclusion, it was suggested that the activation of catecholamine biosynthesis under social stress in hypothalamus and brain stem of male mice was due to the TH activation and increase of its gene expression.

[The significance of the genotype and individual behavioral characteristics for the manifestation of the dominant phenotype in mouse micropopulations]. / Znachenie genotipa i nekotorykh individual'nykh osobennostei povedeniia dlia proiavleniia dominantnogo fenotipa u myshei v mikropopuliatsiiakh.

Influence of genotype and such individual characteristics as locomotor and exploratory activity, aggressiveness and emotionality, was studied in male mice. Males F1 and males of the parent line PT had high level of social dominance. F1 had high level of aggressiveness, and low emotionality, medium level of locomotor and exploratory activity. Significance of these individual behavioural characteristics for dominant behaviour is discussed.

[Genetic-neurochemical analysis of the role of brain catecholamines in the manifestation of dominance in male mice in micropopulations]. / Genetiko-neirokhimicheskii analiz uchastiia katekholaminov golovnogo mozga v proiavlenii dominirovaniia samtsov myshei v mikropopuliatsiiakh.

The ability of male mice to dominate in micropopulations, in connection with brain catecholamines was studied. It was shown that the F1 obtained from breeding PT and CBA/Lac which have respectively large and small numbers of high rank males were of high level of dominance in micropopulations. Moreover, they had high levels of noradrenaline and dopamine in hippocampus, striatum and brain stem, and low--in hypothalamus.