Behavioral despair in mice after prenatal stress

Maternal stress during pregnancy produced behavioral alterations in both sexes with regard to sexual behavior, aggressive, maternal, lateralization and depression. In the present paper, sex differences for depression in mice was studied. No sex differences between female and male mice groups were observed either in swimming-induced immobility or in the open-field test (ambulation, rearing and boluses). Prenatal stress produced: 1) an increase of immobility time in female mice for swimming-induced immobility, but not in male mice; 2) an increase of ambulation in female mice for open-field test, but not in male mice; 3) there were no significant differences in rearing and boluses between stress and control groups either for female or male mice. Prenatal stress increases the risk of depression and locomotor activity in adult female mice.     

Temporal stability of novelty exploration in mice exposed to different open field tests

We investigated behavioural activity and temporal distribution (patterning) of mouse exploration in different open field (OF) arenas. Mice of 129S1 (S1) strain were subjected in parallel to three different OF arenas (Experiment 1), two different OF arenas in two trials (Experiment 2) or two trials of the same OF test (Experiment 3). Overall, mice demonstrated a high degree of similarity in the temporal profile of novelty-induced horizontal and vertical exploration (regardless of the size, colour and shape of the OF), which remained stable in subsequent OF exposures. In Experiments 4 and 5, we tested F1 hybrid mice (BALB/c-S1; NMRI-S1), and Vitamin D receptor knockout mice (generated on S1 genetic background), again showing strikingly similar temporal patterns of their OF exploration, despite marked behavioural strain differences in anxiety and activity. These results suggest that mice are characterised by stability of temporal organization of their exploration in different OF novelty situations.     

去胡须对大鼠行为及桶状皮层的影响

目的:研究外周去胡须后大鼠行为及桶状皮层(barrel cortex,BC)的可塑性变化。方法:SD大鼠随机分组(n=4):正常对照(A组),出生后第2天去除双侧颊脂垫组(B组),出生后第2天去除右侧颊脂垫组(C组),出生后1～5d每天剪右侧胡须,从出生后第5天起不剪由其胡须自由生长组(D组)。出生后第30天时称体重,测量左侧D2胡须长度,观测行为学变化(如狭缝实验、自由探索行为和趋壁行为)。采用细胞色素氧化酶组织化学法研究barrel排列与发育情况。结果:A组能迅速辨别出正确狭缝并钻入,平均用时(5.6±2.3)s;B组大鼠只有当鼻尖碰到狭缝壁时才会钻入狭缝。C组大鼠当其右侧脸颊靠近狭缝时,不能辨别出狭缝,只有当其掉转身体,用左侧胡须探测时才可能迅速钻入正确的狭缝。D组的表现同C组,B、C、D组大鼠进入正确狭缝的所用时间均显著长于A组(P0.01,P0.05,P0.01)。去除双侧颊脂垫的大鼠其左趋壁时间、右趋壁时间以及总趋壁时间均较正常大鼠短。去除右侧颊脂垫组的大鼠右趋壁时间也显著短于正常(P0.05)。四组大鼠左侧D2胡须长度以及体重均无显著差异。从出生后第2天时一直剪除右侧胡须的小鼠在出生后第30天时发现其barrel变小,排列较混乱,barrel之间的界限不清,皮层细胞色素氧化酶(CO)反应的灰度明显变淡。结论:外周去传入不引起大鼠体重改变及残留胡须长度的代偿性改变,但可引起其趋触及探索行为方面的改变。外周去传入可导致barrel形状及排列的可塑性变化。     

Physostigmine effects on activity and reactions to novelty

Effects of 4 doses of physostigmine on reactions to novelty, rearing and ambulation in rats were observed in an exploration box which allowed free choice of novel and familiar halves. All 3 responses tended towards decreases with higher doses but, whereas this trend was significant for rearing and ambulation, it was only suggestive for reactions to novelty. The results were discussed in the light of views on cholinergically controlled habituation processes.     

Endocannabinoids render exploratory behaviour largely independent of the test aversiveness: role of glutamatergic transmission

To investigate the impact of averseness, controllability and familiarity of a test situation on the involvement of the endocannabinoid system in the regulation of exploratory behaviour, we tested conventional and conditional cannabinoid receptor type 1 (CB1)-deficient mice in behavioural paradigms with different emotional load, which depended on the strength of illumination and the ability of the animals to avoid the light stimulus. Complete CB1 null-mutant mice (Total-CB1-KO) showed an anxiogenic-like phenotype under circumstances where they were able to avoid the bright light such as the elevated plus-maze and the light/dark avoidance task. Conditional mutant mice lacking CB1 expression specifically in cortical glutamatergic neurons (Glu-CB1-KO), in contrast, failed to show a similar phenotype under the same experimental conditions. However, both mutant lines showed increased avoidance of open arm exploration during a second exposure to the elevated plus-maze. If tested in situations where the fear eliciting light could not be avoided, Total-CB1-KO mice showed increased thigmotaxis in an open field, decreased social investigation and decreased novel object exploration under aversive light conditions, but not under non-aversive low light. This time, Glu-CB1-KO also showed decreased exploratory behaviour towards objects and conspecific juveniles and increased thigmotaxis in the open field. Taking into consideration that the behavioural performance of wild-type mice was only marginally affected by changes in light intensities, these data indicate that the endocannabinoid system renders exploratory behaviour largely independent of the test averseness. This process differentially involves endocannabinoid-controlled glutamatergic transmission, depending on the controllability of the test situation.     

Effects of adrenalin on novelty choices and activity in rats

Rearing, ambulation and occupancy of the novel half of an exploration box were observed in Wistar albino rats following intraperitoneal injections of saline, 0.03 or 0.06 mg/kg adrenalin. All three responses were decreased by the drug in a dose-related manner. Adrenalin did not seem to impair ability to discriminate between novel and familiar stimuli since the percentage of rearing that occurred in the novel half was highest in rats who received the 0.06 mg/kg dose. It was concluded that the suppression of novelty choices (and probably rearing and ambulation) by adrenalin was mainly due to its aversive peripheral properties. Pretreatment with 20 mg/kg oxprenolol HCl largely prevented the effects observed earlier, thereby implicating -adrenoceptors in adrenalin's behavioral action.     

Environmental maternal influences on body composition in mice selected for body weight

Summary The effect of the postnatal maternal environment, simulated by rearing mice in litters of three, six or nine, on body weight and body composition was investigated in three lines of mice differing widely in growth rate. The lines were selected for high (H₆) and low (L₆) 6-week body weight while the control line was maintained by random selection. Body weight and weights and percentages of ether extract, water, ash and protein at 21, 42, 63 and 84 days were recorded. With few exceptions, there were positive correlated responses to selection in body weight and in weights of body components. At 21 and 42 days the correlated responses were larger in L₆ mice than in H₆ mice. Body weight and weights of body components were larger for mice reared in litters of three than for those reared in litters of nine. Also, mice reared in litters of six were intermediate in body weight and weights of some of the body components between those reared in litters of three and nine. Differences in body weight and weights of body components due to postnatal maternal environment were small by comparison with differences due to genetic line. There were significant line by maternal environment interactions in body weight at 21 days and in ether extract weight at 21 and 63 days. Line and maternal environment differences in percentages of body components did not follow any consistent trend. The results for percentages of body components were further complicated by line x maternal environment interactions. In general, both line and postnatal maternal environmental differences in percentages of body components diminished with age.Paper No. 5670 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, North Carolina 27650. The use of trade names in this publication does not imply endorsement by the North Carolina Agricultural Experiment Station of the products named, nor criticism of similar ones not mentioned     

Oxprenolol and diazepam effects on activity,novelty preference and timidity in rats

Effects of two doses each of oxprenolol and diazepam were observed on rat ambulation, rearing and novelty preference in an exploration box and latency of emergence from a dark to an illuminated area (timidity). Both doses of oxprenolol shortened emergence latencies but had no effect on any measure recorded in the exploration box. Diazepam shortened emergence latencies and decreased rearing and novelty preference in the exploration box in a dose related manner. By reducing timidity both drugs appeared to exert an anxiolytic effect. In view of oxprenolol's lack of effect on centrally mediated novelty preferences and rearing, it was concluded that its anxiolytic action was probably due to its peripheral influence. Diazepam's anxiolytic effect was more likely to involve central influences because of its corresponding disruption of novelty preference and rearing.     

Comparative analysis of the anxiety-related behaviors in four inbred mice

An anxiety-related behavior is an emotional response of an organism, which is quantitatively measured by several behavioral paradigms. We employed two most frequently used behavioral tests, the open field and light-dark exploration, to comparatively analyze the anxiety-like behaviors in four inbred mice. For an accurate recording of movement, motion analysis software was developed that acquires a real-time video input to generate a behavioral path. Effects of the strains on the test results were evaluated by ANOVA with the Newman-Keuls post hoc comparison. Eight different behavioral indices, four from each tests, were grouped into two classes; the results of duration, center crossing, transition, rearing, and ambulation indicate strain differences of FVB/N>C57BL/6J>/=BALB/cA>/=CBA/N (I), while stretched-attend posture, peeping, and defecation show the tendency of FVB/N=C57BL/6J相似文献   

LPA5 receptor plays a role in pain sensitivity,emotional exploration and reversal learning

Lysophosphatidic acid (LPA) is a bioactive lipid acting on the nervous system through at least 6 different G protein‐coupled receptors. In this study, we examined mice lacking the LPA₅ receptor using an extensive battery of behavioral tests. LPA₅‐deficient mice showed decreased pain sensitivity in tail withdrawal, faster recovery in one inflammatory pain procedure (complete Freund's adjuvant‐induced inflammation) and attenuated responses under specific neuropathic pain conditions. Notably, deletion of LPA₅ also induced nocturnal hyperactivity and reduced anxiety in the mutant mice. Several exploratory tasks revealed signs of reduced anxiety in LPA₅ knockout mice including increased visits to the arena center and reduced thigmotaxis in the open field, and more open arm entries in the elevated plus maze. Finally, LPA₅ knockout mice also displayed marked reduction in social exploration, although several other tests indicated that these mice were able to respond normally to environmental stimuli. While learning and memory performance was not impaired in LPA₅‐deficient mice, we found differences, e.g., targeted swim strategy and reversal learning, as well as scheduled appetitive conditioning that might indicate differential motivational behavior. These results imply that LPA₅ might be involved in both nociception and mechanisms of pain hypersensitivity, as well as in anxiety‐related and motivational behaviors. These observations further support the proposed involvement of LPA signaling in psychopathology.     

Immune response of mice of different inbred lines to Clostridium oedematiens anatoxin

Mice belonging to a number of inbred strains were immunized intradermally with Cl. oedematiens alpha-toxoid. The immunization was repeated 30 days later. On the 20th and the 30th days after the first injection and on the 10th day after the second one the antibody level against the toxoid was determined in the blood of mice by the passive hemagglutination test. The maximum response to the primary immunization was observed in the mice of the C3H strain, and the minimum one--in mice of the DBA/2 strain; the difference was more than 30-fold. The rest of the strains used in the test (A,CBA, BALB/c, AKR, CC57BR) displayed an intermediate level of the immune response. The differences reduced after the repeated immunization. The immune response to this antigen in mice is supposed to be genetically controlled.     

Lack of a distinctive behavioural effect of chromogranin-derived peptides in rodents.

Chromogranins are neuropeptide precursors stored in large dense core vesicles in which they are processed to smaller peptides. Although these peptides are widespread in the CNS, it is still unknown if they are behaviourally active. For example, even though secretoneurin, a 33-amino acid peptide derived from secretogranin II, was shown to induce release of dopamine from rat striatal neurons, work on the functional significance of this result is still missing. In order to investigate the behavioural effects of chromogranin-derived peptides, we studied the total locomotor activity and rearing behaviour of male albino Sprague-Dawley rats in the open field experimental paradigm. Measurements were performed every 5 min during half an hour before and 2 h after an intracerebroventricular injection of GE-19, GAIPIRRH, secretoneurin or vehicle. None of the tested chromogranin-derived peptides (at a concentration of 20 microM) affected locomotion and rearing behaviour. However, the administration of secretoneurin and GAIPIRRH increased the thigmotaxis, suggesting a possible anxiolytic action. In male Swiss albino mice, which were tested in the black-and-white box paradigm, only GE-19 produced sedation at a dose of 0.72 nmol in 41% of the mice. Overall, there is only little evidence that any of the examined chromogranin-derived peptides produces a behaviourally significant effect, even when given intracerebroventricularly.     

Daily repeated magnetic field shielding induces analgesia in CD-1 mice

We have recently observed that a single exposure of mice to a magnetically shielded environment can attenuate opioid induced analgesia. Here, we report the effect of repeated exposures to the same magnetically shielded environment. Adult male Swiss CD-1 mice were placed in a Mu-metal lined box or an opaque Plexiglas box (sham condition) for 1 h per day for 10 consecutive days. Nociception was measured as the latency time to a foot lift/lick in response to an aversive thermal stimulus (hotplate analgesiometer, 50 +/- 1 degrees C) before and immediately after exposure. Multiple experiments were conducted in which thermal latency was tested on each of the 10 days or on days 1, 5, and 10, with some utilizing post-exposure testing only. It was shown that mice can detect and will respond to the repeated absence of the ambient magnetic field, with a maximum analgesic response occurring over days 4-6 of exposure and returning to baseline thereafter. The effect was robust, independent of pre-exposure and intermittent testing, and seems to be opioid related, since the results obtained on day 5 were similar to those from a 5 mg/kg dose of morphine and were abolished with the opioid antagonist, naloxone.     

Effect of Time of Separation from Mother on Behavior in Open Field and on State of the Sympathoadrenal System in Rats Reared under Conditions of Social Isolation

The level of catecholamine excretion with urine and behavior in the open field test were studied in male Wistar rat pups separated from female at the age of 17, 21, 30, and 36 days and reared subsequently for 40 days under conditions either of social isolation or in the group with their kin. It was shown that in rats weaned at the age of 17 and 21 days, the subsequent rearing in isolation led to an increase of the urinary excretion of adrenaline and a decrease, of noradrenaline. After isolation at the 30th day, there was revealed an increase of the excretion level both of adrenaline and of noradrenaline. The social isolation also leads to an increase of horizontal motor activity in rats weaned at the age of 17 days and to a decrease of this activity in rats weaned at the 30-day age. After isolation at the age of 21 days, an earlier extinguishing of the activity it was observed at repeated testing. Isolation at the age of 36 days, on the contrary, led to a decrease of the extinguishing process. Thus, it is shown that the social isolation produces changes in rat behavior and has a stress effect on the animals; the effect of isolation depends on duration of the rearing of rats in the nest with the female.     

Food consumption and body composition in mice selected for high wheel-running activity

The effects of genetic selection for high wheel running (13th generation) and prolonged access (8 weeks) to running wheels on food consumption and body composition were studied in house mice (Mus domesticus). Mice from four replicate lines selected for high wheel-running activity ran over twice as many revolutions per day on activity wheels as did mice from four replicate control lines. At approximately 49 days of age, all mice were placed individually in cages with access to wheels and monitored for 6 days, after which wheels were prevented from rotating for the "sedentary" individuals. During the experiment, five feeding trials were conducted and body mass was measured weekly. After 8 weeks, body composition was measured by hydrogen isotope dilution. Across the five feeding trials, mice in the "active" group (wheels free to rotate) consumed 22.4% more food than mice in the "sedentary" group (wheels locked); mice from the selected lines consumed 8.4% more food than mice from the control lines (average of all trials; body mass-corrected values). In females, but not males, we found a significant interaction between selection and wheel access treatments: within the "active" group the difference in food consumption between selected and control animals was greater than in the "sedentary" group. At the end of the study, mice from the "active" and "sedentary" groups did not differ significantly in body mass; however, mice from the selected lines were approximately 6% smaller in body mass. Estimated lean body mass did not differ significantly either between selected and control lines or between wheel-access groups (P>0.3). Mice from selected lines had lower total body fat compared to mice from control lines (P=0.05; 24.5% reduction; LSMEANS) as did mice from the "active" compared to "sedentary" group (P= 0.03; 29.2% reduction; LSMEANS). Under these conditions, a sufficient explanation for the difference in body mass between the selected and control lines was the difference in fat content.     

用适应性实验对ICR、BALB/c和C57BL/6小鼠探索行为及记忆能力的评价

用洞板仪和旷场行为红外线检测系统对远交群ICR小鼠、近交系BALB/c小鼠和近交系C57BL/6小鼠的探洞、直立和跨格行为进行了测试,并通过适应性实验比较了它们的探索行为和记忆能力。研究发现:在各项试验中,ICR小鼠表现出最强的探索能力,而C57BL/6小鼠的探索能力最差;ICR小鼠还表现出比另外两个品系小鼠更强的对新环境的适应性,其记忆也明显优于C57BL/6小鼠。实验结果提示:小鼠探洞行为的适应性实验可以用来测试小鼠的记忆能力,而小鼠的直立行为在一定程度上也反映了其对周围环境、事物的探索和认知。这些结果为今后在研究小鼠神经生物学时的行为学指标选择问题提供了参考依据,同时也提示了在进行小鼠行为学实验时,根据不同研究目的选择不同品系的重要性。     

Host selection by the generalist aphid Myzus persicae (Hemiptera: Aphididae) and its subspecies specialized on tobacco, after being reared on the same host

Decision-making during host selection by phytophagous insects has proved to be related to host range, with specialists taking faster decisions than generalists; however, this pattern fails to materialize in some host selection studies performed with aphids. Differences found in testing designs point to rearing effects on aphid host selection. To test whether specialization patterns derive from the nature of the aphid or as a consequence of rearing environment, host selection behaviours were compared between the generalist Myzus persicae (Sulzer) s.s. and its subspecies specialized on tobacco when reared on a common host and offered the choice of an alternative host and a non-host plant. Pre-alighting (host finding and attraction towards host volatiles) and post-alighting (leaf surface exploration and probing) behaviours did not differ between the generalist and the tobacco-specialist, except in the allocation of time to probing behaviour; furthermore, all specialists chose the host on which they performed best. Thus, although the specialist was not faster than the generalist, it showed a higher level of commitment to its preferred host plant.     

Liver-derived IGF-I regulates exploratory activity in old mice

Growth hormone (GH) replacement in hypopituitary patients improves well-being and initiative. Experimental studies indicate that these psychic effects may be reflected in enhanced locomotor activity in mice. It is unknown whether these phenomena are mediated directly by GH or by circulating IGF-I. IGF-I production in the liver was inactivated at 6-10 wk of age (LI-IGF-I-/- mice), resulting in an 80-85% reduction of circulating IGF-I, and, secondary to this, increased GH secretion. Using activity boxes on three different occasions during 1 wk, 6-mo-old LI-IGF-I-/- mice had similar activity levels, and 14-mo-old mice had a moderate but significant decrease in activity level, compared with control mice. At 20 mo of age, the LI-IGF-I-/- mice displayed a more prominent decrease in activity level with decreased horizontal activity throughout the test period, and at day 1, there were several signs of an altered habituation process with different time patterns of locomotor activity and horizontal activity compared with the control mice. At days 3 and 5, rearing activity was lower in the 20-mo-old LI-IGF-I-/- mice. Anxiety level was unaffected in all age groups, as measured using the Montgomery's elevated plus-maze. In conclusion, old LI-IGF-I-/- mice displayed a decrease in both horizontal and rearing (exploratory) activity level and an altered habituation process. These results indicate that liver-derived IGF-I mediates at least part of the effects of GH on exploratory activity in mice.     

Manifestation of active and passive defensive behavior in juvenile rats

The dynamics of freezing and flight reactions in juvenile rats was investigated. The rats were tested on the 20th, 25th, 35th, and 40th postnatal days. A sound of 6-sec duration (bell) was used as a threatening stimulus. The following parameters were recorded: number of rearing reactions and defecations within 5 min prior to stimulation, reactions to the bell, latent periods and durations of freezing reactions, freezing posture rigidity, and time of recovery of movements after freezing. It was shown that the intensity of freezing reduced in the period from the 20th to 35th postnatal day. The flight reactions were highest on the 25th and 40th days. Correlations between freezing indices and numbers of rearing and defecation reactions were different in rats of all age groups. The results suggest that the structure of defensive behavior changes with maturation of principal defensive reactions in rats within the first 40 postnatal days.     

利用黑色斑蚕作亲本、选育日系普斑限性品系

根据家蚕Bombyx moli斑纹互作原理,利用2032限性品种的雌,与自然突变体雄杂交。F2代出现分离,于是淘汰所有黑色斑蚕,只留下普斑蚕和素斑蚕,即得到新限性普斑系。新限性品系得到后,做连续3代的系统选育,其中F3代为蛾区混合育,F4～F5代采用单蛾育。蛾区混合育着重个体选择,单蛾育以蛾区选择为主,个体选择为辅。性状基本稳定后,即初步对其作主要经济性状的测定。结果显示:新限性品系在5龄经过、全龄经过上比两亲本略短。在全茧量、茧层量、茧层率几项指标上较两亲本为优,分别比两亲本平均值提高31%、38%、5%。