[Prolactin-releasing peptide increases rat anxiety].

BACKGROUND: Prolactin-releasing peptide(Prl-RP), in addition to stimulating the production of prolactin, interacts with various parts of the central nervous system, participating in the implementation of many functions that are reflected in behavior. AIM: The effect of Prl-RP on the anxiety of white Wistar rats was studied since there were no data in the literature on the relationship between Prl-RP and anxiety. MATERIALS AND METHODS: Anxiety was assessed in two tests. In the elevated plus-maze (EPM), the time spent in the open arms and the number of edge reactions were recorded. In the social preference test, the time spent near a stranger, near a familiar individual, and in neutral territory were recorded. RESULTS: The administration of Prl-RP at a dose of 10-10 M with a volume of 10 µl in each nostril reduced the time spent by the animals in the open arms of the EPM, and the number of edge reactions. For testing the social interaction, animals were pre-selected for high or low levels of anxiety in the EPM. In rats with initially low levels of anxiety, Prl-RP reduced the time spent near a stranger, indicating an increase in anxiety levels. The behavior of rats with initially high levels of anxiety did not change after application of the Prl-RP. CONCLUSION: The results of our experiments indicate that the intranasal administration of Prl-RP increases the anxiety of rats.

[Intranasal application of a thyrotropin-releasing hormone attenuates state-anxiety of the rats].

During the experiments we investigated the influence of thyrotropin-releasing hormone (TRH) on the changes in the behaviour of white rat (Rattus norvegicus) males (n = 90), induced by light uncontrolled impact. After two-week procedure of handling male rats were tested using elevated plus-maze to determine the basal level of anxiety, locomotor and investigative activity and emotionality. A month later we investigated the influence of intranasal administration of TRH-solution (10(-10) M) in a volume of 20 mkl on the anxiety-level increase, induced by stress: short electric foot-shocks. Four hours later animals were tested in the elevated plus-maze. In vehicle-treated animals we detected the increase of anxiety and emotionality level and the decrease of locomotor and investigative activity. In contrast there was no increase of anxiety and emotionality in TRH-treated rats. As to the locomotor and investigative activity, it decreased in TRH-treated animals as well as inthe vehicle-treated. It shows the specific influence on the level of anxiety, which doesn't affect other components of stress-induced behavioral changes Present results suggest TRH as a potential anxiolitic.

[Active coping style as a risk factor of depressive-like disorders after cronic mild stress].

Effect of chronic mild uncontrollable stress on behaviour was studied on rats with opposite behavioural coping styles--active and passive. In a population of outbred animals, specimens with opposite coping style of behaviour were selected based on their reactions in the active avoidance (AA) test. Both groups were subjected to chronic mild stress during 30 days and tested for depressive behaviour (forced swim test, 32% glucose solution consumption test), anxiety (elevated plus maze) and learning (AA test). The behavioural test showed that depressive behaviour after chronic mild stress is more common in animals with active behaviour strategy.

Influenza vaccination in healthy working adults in Russia: observational study of effectiveness and return on investment for the employer.

BACKGROUND: All age groups are affected by influenza infection, resulting in significant medical and economic burden. Influenza infection of healthy working adults can have a marked effect on companies due to lost work days and reduced productivity. Studies in corporate settings have shown that vaccination programmes reduce this burden, although there is a lack of data in Eastern European countries. OBJECTIVES: To determine the effectiveness of influenza vaccination in healthy working adults in Russia and the economic benefits of such a programme from an employer's perspective. METHODS: In a prospective, non-randomized, non-placebo-controlled, observational study, healthy vaccinated and unvaccinated adults employed at the Russian Railways Public Corporation were followed for 8 months during the 2005-6 influenza season using questionnaires. A first questionnaire was administered at inclusion to collect general employee information; a second questionnaire was administered to collect data on post-vaccination adverse events; and monthly questionnaires were used to gather data on influenza-like illness (ILI). Effectiveness calculations and cost analyses were performed to evaluate the impact of the influenza vaccination programme on employee productivity and costs for the employer. The study vaccine used was the trivalent, inactivated, split vaccine Vaxigrip® (sanofi pasteur, France). RESULTS: A total of 1331 employees volunteered for the study: 701 were vaccinated and 630 were not. The vaccine effectiveness was 70.4% against ILI events and 80.8% against sick leave days. Assuming that employees working with ILI symptoms had a reduced level of productivity (30-70% of normal), cost savings per vaccinated employee ranged from &U20AC;2.13 to &U20AC;5.43. CONCLUSIONS: This study showed that an influenza vaccination programme significantly reduced ILI episodes and absenteeism, and may provide a positive return on investment for the employer.

[Social preference of white rats with high and low anxiety].

In outbred population of white rats (Rattus norvegicus), we picked out two groups of male animals with high (HA) and low levels of anxiety (LA). Social preference for a familiar or unfamiliar conspecific were studied. The rats (n = 85) were housed five per cage for two months before the experiment. Thus, the social structures in every cage were stable. The anxiety was tested in an elevated plus-maze. For social interaction test we used the box, in which two opposite corners were separated with perforated transparent Plexiglas walls. A mate of a tested subject was placed into one corner the cage, an unfamiliar animal was put into another corner. During five minutes we measured the time spent near each of the conspecifics and in neutral area. For both high- and low-anxiety groups, the time spent in the neutral area was less than 60 sec. i.e. rats in a novel environment spent much more time in social contacts than in environmental exploration. Rats with high anxiety spent 88 +/- 32 s and 155 +/- 35 s close to an unfamiliar subject and a cage mate, respectively. On the contrary, the measurements for rats with low anxiety were 200 +/- 40 s for an unfamiliar subject, and 65 +/- 32 s for a cage mate. Consequently, high-anxiety rats preferred contacts with a familiar conspecific, whereas low-anxiety rats preferred to contact with an unfamiliar conspecific.

[Forensic chemical detection of furadan].

Isolation of furadan from biological material by ethyl acetate is considered. Column chromatography with silicone gel L 100/160micro was used to purify extractions from biological objects. A technique was elaborated for identification and quantitation of furadan in cadavers. It is possible to use this technique in forensic expert examination.

[Patterns of maternal behavior of rats genetically selected for opposite coping styles]. / Materinskoe povedenie u krys s razlichnoi strategiei prisposobleniia.

Maternal behavior of Koltushi High- and Low-avoidance (KHA and KLA) rats strains was assessed over the prewealing period (days 6-21). Ten litters of each strain were observed during the light phase of the light/dark cycle. In a series of experiments, rat pups were taken from the maternal nest and placed into the opposite corner of the cage. The following parameters of the maternal behavior were recorded: the latency of the first contact with the pups, pup licking, latency of carrying/retrieval of the first pup back to the nest, time of returning to the nest of the whole litter, and mother's spontaneous behavior (grooming and locomotion time) over the course of 10 min of observation. KLA mothers stayed with their pups and took care of them more frequently than KHA mothers during the light phase of the circadian cycle. Time of self-grooming was significantly higher in KHA rats. The highest levels of self-grooming of mothers was registered on the first day of testing. The latency of the first coming to pups after their removal from the nest was lower in KHA rats, but they needed more time to returned all pups to the nest. The experimental evidence suggests that the KHA but not KLA rats with the active coping style and higher stress reactivity display disorders in maternal behavior in a novel situation.

The effects of stages of the estrous cycle on pain thresholds in female white rats.

The effects of stages in the estrous cycle on electrical pain thresholds were studied in white rats in conditions of chronic measurement. On recording day 3, females in the diestrus and estrus stages showed sharp increases in shudder and paw-shuffling thresholds. Females in proestrus and metestrus showed no change in thresholds as compared with those in the first days of recording. Starting from day 7, there were progressive decreases in electrical pain thresholds regardless of the stage of the estrous cycle. Data for all animals showed that regular measurement of pain thresholds induces a smooth two-fold increase in body resistance from day 1 to day 7. This was followed by a sharp drop on day 8, with parallel decreases in body resistance and electrical pain thresholds. Thus, chronic measurement of electrical pain thresholds and body resistance changed in a complex fashion, and threshold values depended on the stage of the estrous cycle.

Learned helplessness or learned inactivity after inescapable stress? Interpretation depends on coping styles.

Researches on uncontrollable events in the post-soviet states are overviewed. In our research, susceptibility to learned helplessness is studied in rats with active (KHA strain) versus passive (KLA strain) coping styles. Inescapable footshocks, but not escapable footshocks, applied to KHA rats induced escape failures, diminished locomotion and coping, reduced measures of anxiety, and resulted in dexamethasone nonsuppression of the brain-hypothalamus-pituitary-adrenal axis--all characteristic of learned helplessness. In contrast, KLA rats demonstrated the same responses upon exposure to both escapable and inescapable stresses. While learned helplessness occurred in KHA rats, it appears that KLA rats exposed to inescapable stress demonstrated learned inactivity based upon the nondifference between effects of escapable and inescapable shocks. Relationships between coping styles and social ranks are discussed. Our and other's results with genetically selected strains suggest active coping in dominant and subordinate subjects, and passive coping in subdominant animals confirm the importance of coping style and its relation to health under stress.

[Rats with passive coping strategy have average, but not low social range]. / Krysy s passivnoi strategiei prisposobleniia obladaiut srednim, a ne nizshim sotsial'nym rangom.

Social ranks were determined in rats with different degrees of activity-passivity in coping style. The dominance status of rats was assessed by their behavior during social interaction and during competition for food and water. Coping styles were determined during initial trials of acquisition of active avoidance in a two-way shuttle box. Animals with passive behavior in a shuttle box had average scores of social ranks. Both dominant and subordinate rats displayed significantly more active behavior than subdominant animals. In additional experiment, the rats were caged as a one male-one female pairs. Two weeks later, the social ranks of males were determined during agonistic interactions. Males were caged in triads, and corticosterone levels were assayed in blood samples taken from the tail veins during the first five days. The corticosterone level was significantly higher in subdominants than in dominants. There was no significant difference between the dominants and subordinates in corticosterone levels. The obtained evidence suggests the passive coping in subdominant rats, whereas the dominant and subordinate animals were more "active" under aversive stimulation.

[Feedback in the stimulus-response system determines stress specifics]. / Obratnaia sviaz' v sisteme "stimul-reaktsiia" opredeliaet osobennosti stressa.

The paper surveys controllability in the stress theory. Uncontrollable action is perceived by living organisms in a principally different way than the controllable one and induces persisting pathological changes. The controllability, i.e. presence of a feedback in the stimulus/response system, is determined by an interaction of the medium factors and a strategy of subject's behaviour. A passive strategy proves to be optimal for adaptation under the conditions when an animal cannot change unfavourable medium conditions. The authors base their theoretical statements on their own experimental studies as well as literature references analysis.

[Intersex and interspecies differences in sucrose consumption by rats with various behavioral strategies]. / Mezhpolovye i mezhlineinye razlichiia v potreblenii sakharozy krysami s razlichnoi strategiei povedeniia.

Sucrose consumption by male and female rats during active avoidance acquisition was measured in two rat strains: KLA (Koltushi low avoidance) and KHA (Koltushi high avoidance) selected for divergent performance in a shuttlebox. Under resting condition, there were no interstrain difference in sucrose consumption by males, but KHA females consumed significantly less sucrose than KLA females. Active avoidance acquisition during five consecutive days decreased sucrose consumption in KLA males and did not change sucrose consumption in KHA males. Within a week after exposure to the stress, the sucrose consumption by KLA males returned to its normal values, and KHA males consumed significantly more sucrose. The active avoidance conditioning did not affect sucrose consumption in females of both strains. Substitution of 32% solution for 4% produced on the first day a sharp decrease in sucrose consumption in males of both strains, while females sharply increased consumption of the diluted solution over the next four days of observation. During this time, males returned to consumption of the same volume of the solution despite its decreased concentration. The findings suggest that the exposure to the escapable stress induces the negative affect only in KLA males.

[Effect of estrous cycle phase on pain threshold in female white rats]. / Vliianie stadii éstral'nogo tsikla na bolevye porogi samok belykh krys.

Pain thresholds and body resistance in female Wistar rats were determined during estrous cycle stages. The flinch and shuffle thresholds were increased on the 3rd day of measurement in diestrus and estrus but not in proestrus and metestrus as compared with the thresholds during the 1st day of recording. The thresholds decreased as of the 7th day to the 14th day. Daily threshold measurements raised the body resistance on the 7th day of recording. In contrast to the pain thresholds, the body resistance change had not a stage-dependent character.