Development of Amnesia in Different Mouse Strains

We studied passive avoidance retrieval after amnestic stimulation (arrest in unsafe section of the experimental setup) in C57Bl/6J, BALB/c, CBA/Lac, AKR/J, DBA/2J, C3H/HeJ, and ASC/Icg mice. We demonstrated resistance to amnestic stimulation in mice with high predisposition to freezing reaction (ASC/Icg) and memory deficit in other mouse strains.     

Immune response in mice of a new strain ASC (antidepressants sensitive catalepsy)

Inherited predisposition of ASC mice with depressive behavior to catalepsy was accompanied by a significant decrease in the immune response to sheep erythrocytes (compared to parent strains CBA and AKR). The degree of immunosuppression was highest on day 5 after immunization. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 8, pp. 188–190, August, 2007     

Inheritance of predisposition to catalepsy in mice

Pinch-induced catalepsy (excessive freezing) was studied in mice of nine inbred strains. The CBA/Icg strain had the highest predisposition to catalepsy, with 56% males and 73% females exhibiting 120-s immobility after four tests. A Mendelian analysis of predisposition to catalepsy was performed on CBA/Icg and AKR/J mice contrasting in this trait. Reciprocal F₁ hybrids did not display freezing after 10 tests. The number of cataleptic and noncataleptic animals among the F₂'s and in the families of the CBA×F₂ backcrosses agreed with the hypothesis that the pronounced predisposition to catalepsy in the CBA/Icg mice was determined by a single autosomal locus in homozygous recessive condition.     

Benzodiazepine Reception in C57Bl/6 and BALB/c Mice Depending on the Type of Stress Factor

Specific binding of ³Н-fl unitrazepam with synaptosomal membranes after exposure to open field test and “contact with predator” test was measured in C57Bl/6 and BALB/c mice. Stress-induced decrease in benzodiazepine binding after open field test was observed only in BALB/c mice and after contact with predator in both animal strains.     

Learning and Extinction of a Passive Avoidance Response in Mice with High Levels of Predisposition to Catalepsy

This report presents results obtained from comparative analysis of learning and the dynamics of extinction of a conditioned passive avoidance response in ASC mice, which were bred for a high level of predisposition to catalepsy, and in CBA and AKR mice. The following findings were obtained: 1) impairments to the extinction of the memory of fear represent an important symptom of depression in ASC mice; 2) extinction is delayed in CBA mice; and 3) new inhibitory learning occurs quickly in AKR mice. Prolonged retention of the fear memory in ASC mice appears to be related to increased anxiety on prolonged testing without a punishment. The deficit of inhibition of the fear reaction in ASC mice allows this strain to be regarded as a genetic model of depression. Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 94, No. 6, pp. 609–616, June, 2009.     

Effect of 5-HT2C receptor antagonist RS 102221 on mouse behavior

Injection of RS 102221 (selective antagonist of serotonin 5-HT_2C receptors) in a dose of 2 mg/kg reduced anxiety of mice in the light-darkness test and decreased the amplitude of the startle reflex. RS 102221 in a dose of 1 mg/kg reduced prestimulus inhibition of the startle reflex. No behavioral changes in Porsolt test and motor activity in the open field test were detected. Hence, RS 102221 is characterized by selective anxiolytic activity, and 5-HT_2C receptors are involved in the mechanisms of anxiety and startle reflex formation. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 7, pp. 86–89, July, 2006     

Level of liver fibrosis and immune status of mice of different age after heroin treatment and long abstinence

Young and middle-aged CBA mice were injected with “street” heroin in increasing doses for 14 days. Volume density of perisinusoid argirophilic fibers increased in both age groups (the increase being more pronounced in middle-aged mice), while the levels of spontaneous, LPS-and ConA-stimulated splenocyte proliferation decreased in young mice. Six months after heroin discontinuation further progress of liver fibrosis was observed in young mice. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 140, No. 12, pp. 678–680, December, 2005 Municipal Clinical Hospital No. 12     

Studies of the Relationship between Catalepsy and Anxiety,Aggression, and Depression-Like Behavior Using Congenic Mouse Strains

Catalepsy is a passive-defensive freezing reaction produced in response to threatening stimuli which in exaggerated form constitutes a syndrome of impaired brain function. In mice, the major gene determining susceptibility to catalepsy has been located in the distal 55–75 cM fragment on chromosome 13. Two congenic strains were constructed: AKR.CBA-D13Mit76 and AKR.CBA-D13Mit78, which carry two fragments, i.e., 55–71 and 71–75 cM of chromosome 13, respectively, which were transferred from cataleptic strain CBA to the genome of the non-cataleptic AKR strain. Half of AKR.CBA-D13Mit76 mice were found to show pronounced catalepsy, comparable to that of animals of the donor strain CBA. Decreases in investigative behavior in the open field test were also seen, along with decreases in intermale aggression, as compared with AKR mice, while there were no differences in the forced swimming test. AKR.CBA-D13Mit78 mice showed no differences in comparison with the parent AKR strain in tests for catalepsy, in the open field test, the forced swimming test, or tests for aggression.     

Functional roles of the monoaminergic and aminoacidergic mechanisms of the dorsal pallidum in anxiety of different aversive origins

Microinjections of serotonin and glutamic acid into the globus pallidus in conditions of free selection between a light and a dark chamber showed these substances to have antiaversive activity in rats in the “threatening situation” test but not in the “illuminated area” test. Local administration of dopamine and GABA into this basal ganglia formation had no effect on the mechanisms of voluntary movement but countered anxiety states in both behavioral models. These results provide evidence that the neurotransmitter systems of the dorsal pallidum have different degrees of involvement in the operative control of behavior when the modality of the aversive stimulus changes. __________ Translated from Zhurnal Vysshei Nervnoi Deyatel’nosti imeni I. P. Pavlova, Vol. 57, No. 1, pp. 86–90, January–February, 2007.     

Structural and functional organization of bone marrow of AKR/J mice during aging

Expression of sialoadhesin and erythroblast receptors on macrophages and structural and functional organization of the bone marrow during aging were studied on AKR/J mice. It is shown that progressive accumulation of granulocyte hemopoietic islets can be a compensatory reaction to a decreased capacity of their central stromal elements to bind young granulocytopoietic cells. Expression of erythroblast receptors on macrophages from 4-month-old AKR/J mice is considerably higher than in young and old mice and than in 4-month-old (CBA×AKR)F₁ mice. The high concentration of erythroid precursors in the bone marrow of AKR mice is not accompanied by enhanced erythropoiesis, probably due to a decreased yield of erythroid hemopoietic islets. Thus, a marked imbalance in structural and functional organization of the bone marrow during aging is noted in highly leukemic AKR/J mice, which provides a basis for the development of reliable diagnostic and prognostic criteria of leukemic progression. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 3, pp. 266–268, March, 1998     

Effect of immunization with sheep red cells on rat behavior

The changes of behavior of rats in the “open field” test and the conditioned reaction of passive avoidance during the humoral immune response to a conventional antigen-sheep red cells—are studied. The primary immune response is found to be accompanied by activation of the exploratory component of rat behavior and by a reduced capacity for the development of the passive avoidance reaction in the initial period of antibody production; the development of the secondary immune response led to a short-term increase in locomotor activity. The results point to the effect of the normal immune response on the physiology of rat behavior. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 11, pp. 474–476, November, 1994 Presented by Yu. A. Romanov, Member of the Russian Academy of Medical Sciences     

Functional heterogeneity of the “transporter” of electrogenic ionic pump of the Lumbricus terrestris somatic myocyte membrane

Potential created by electrogenic ionic pumps under conditions of maximum activation in a warm standard ionic medium with K⁺ after preincubation in cold potassium-free solution has two components: a higher ouabaine-insensitive “stationary” component, and a lower “regulatory” component sensitive to ouabaine, furosemide, and removal of Cl⁻ or Ca²⁺ from the medium. Functional heterogeneity of electrogenic ionic pumps is hypothesized implying the existence of two components: “stationary” (not regulated extracellularly) and “regulatory” (controlled and directly related to active Cl⁻ transfer). __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 142, No. 12, pp. 678–680, December, 2006     

Effects of single episodes of severe stress on the behavior of male and female CBA/Lac and C57BL/6J mice

Experiments were performed to compare the behavior of male and female mice of the inbred strains CBA/Lac and C57BL/6J in the open field test after single episodes of severe stress imposed by forced swimming. Testing was performed 2 h (first test) and one day (second test) after stress. Control animals were intact males and females of these strains, and were also tested in the open field on two sequential days. Both male and female CBA/Lac mice showed increases in the latent period of excursions from the center of the field 2 h after stress. This change persisted to the second test in female CBA/Lac mice. In female C57BL/6J mice, there were changes in four of seven behavioral measures 2 h after stress, though at one day their behavior was as in control individuals. Stress had virtually no effect in males of this strain, only increasing the number of grooming acts in the first test. In addition, detailed analysis of the effects of repeat testing in control and stressed individuals of these mouse strains also revealed interstrain and gender-related differences in the effects of stress. The possible existence of increased basal (trait) and situational (state) anxiety in female C57BL/6J and CBA/Lac mice respectively is discussed. __________ Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 92, No. 5, pp. 567–577, May, 2006.     

Mechanisms of formation of micronuclei in somatic cells of tailless amphibians normally and under the effect of N-nitroso-N-methylcarbamide

We studied the relationship between mitotic regimen and incidence of micronuclei in liver and bone marrow cells of tailless amphibians under the effect of genotoxic carcinogen N-nitroso-N-methylcarbamide. Micronuclei appeared in amphibian somatic cells normally and after mutagenic exposure as a result of abnormal mitosis and of “interphase chromatin diminution”. This latter variant was most incident in lymphoid cells, presenting as “caudate nuclei”, which should be taken into consideration when interpreting findings of micronucleus analysis. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 2, pp. 217–220, February, 2006     

Psychostimulant effect of synthetic dermorphin analog

The effect of a dermorphin analog on learning was studied in a Wistar rat model of the complex food-seeking task. The preparation decreased the degree of anxiety in a dose-independent manner. In a dose of 50 μg/kg it increased the number of “well”-learning rats by intensifying the learning process in rats with initially suppressed cognitive activity. In a dose of 150 μg/kg, the opioid decreased the number of “well”-learning rats due to disturbance of motivation mechanisms, which was manifested in behavioral instability. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 9, pp. 252–255, September, 1998     

Promoting effect of <Emphasis Type="Italic">o</Emphasis>-aminoazotoluene on hepatocarcinogenesis is accompanied by the increase in inflammatory and proliferative processes in liver tissue and decrease in the concentration of free thyroxin in the blood

o-Aminoazotoluene in noncarcinogenic doses promoted the development of liver tumors in female ICR mice induced by administration of diethylnitrosamine during early ontogeny. Severe inflammatory infiltration and proliferation of oval cells were found in liver tissue of these animals. The concentration of free thyroxin decreased in the blood. Our results supplement published data that promoters of hepatocarcinogenesis inhibit thyroid function. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 12, pp. 672–675, December, 2007     

Tissue reactions to modern suturing material in colorectal surgery

Morphological changes in the wall of the large intestine were studied after its manual suturing by a double-row interrupted suture with modern suture threads. Light and scanning electron microscopy showed “fuse properties” and “sawing effect” of polyfilament twisted threads (e.g. vicryl). Monofilament threads were free from these drawbacks and therefore were preferable. Metal elastic threads on the basis of titanium-nickelide alloys caused no inflammatory changes in tissues. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 143, No. 6, pp. 714–717, June, 2007     

Opposite effects of antioxidants on anxiety in Wistar and OXYS rats

Passive behavior in the open field test and high anxiety in an elevated plus-maze develop in OXYS rats by the age of 3 months and are regarded as manifestations of early aging. We studied the possibility of preventing these disturbances with vitamin E and whortleberry extract (20 mg/kg for 45 days from the age of 1.5 months). Whortleberry extract alone increased horizontal activity and reduced anxiety of OXYS rats, while anxiety in Wistar rats increased significantly after treatment with both preparations, and especially with vitamin E: the number of entries into open arms of the elevated plus-maze and the time spent there decreased. The results necessitate comprehensive evaluation of the aftereffects of long-term use of antioxidants, acknowledged geroprotectors intended for preventive use. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 6, pp. 685–688, June, 2006     

Coronarographic and pathomorphological characteristics of unstable atherosclerotic plaques in acute coronary syndromes

The proximal segments of the main coronary vessels are the most often localization of “soft” unstable atherosclerotic plaques. The maximum number of plaques developed in the anterior descending branch of the left coronary artery. Pathognomonic relationship was found between the type of these plaques (with ulceration, rupture, thrombosis) and certain acute coronary syndrome. It was shown that the criteria of the plaque instability correlated with clinical manifestations of coronary syndromes. The bases and effects of “pathological” vascularization of unstable atherosclerotic plaques on the angioarchitectonics and hemodynamics of the heart were determined. Dissociation between myocardial vascularization degree and myocardial blood supply index was detected, which underlies the development of “unstable” myocardium in patients with acute coronary syndromes. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 144, No. 8, pp. 229–235, August, 2007     

Disturbances in the integrative activity of the rat brain after bilateral focal compression ischemia of the frontal cortex

Pathomorphological changes and disturbances in the integrative activity of the central nervous system of rats are studied after bilateral compression ischemia of the frontal cortex. Bilateral compression of the frontal cortex is shown to result in the formation of limited foci of ischemic necroses in the cortex, which are surrounded by the perifocal zone. This is attended by reduced horizontal motor activity in the “open field” test, as well as by a reduced latency of the conditioned passive avoidance response. The motor activity of operated animals is restored on day 14 postoperation, correlating with regeneration of some damaged neurons in the perifocal zone, whereas the latency of the conditioned passive avoidance response remains markedly reduced. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 12, pp. 568–571, December, 1994 Presented by O. S. Adrianov, Member of the Russian Academy of Medical Sciences