人为疼痛刺激下金色中仓鼠幼鼠叫声的发育过程

金色中仓鼠幼鼠可以利用可听声和超声信号与母鼠进行交流,这些声音可以反映个体的寒冷、饥饿、疼痛等不同生理状态和需求。因疼痛诱发的叫声对于维持幼鼠的存活也有着重要意义。本实验通过录制人为疼痛刺激下,不同日龄金色中仓鼠的叫声,分析并比较了5 - 30 日龄金色中仓鼠不同发声信号特征(可听声出现频次、可听声持续时程、可听声主频率、超声出现频次、超声持续时程、超声主频率)的性别差异;同时记录了幼鼠的两种发声随日龄的变化趋势。结果发现:幼鼠两种叫声的各种参数均未表现性二型现象。幼鼠超声发生频次随日龄增加而逐渐减少。而可听声却正相反,随日龄增加而逐渐上升,并在20 日龄时达到最高峰,之后逐渐下降。可听声持续时程也随日龄而增加。综上,在人为疼痛刺激下,随着日龄增加,幼鼠更倾向于使用可听 声而非超声与母兽进行交流。     

不同年龄大鼠学习记忆能力及旷场行为比较

目的：实验对２２日龄、１月龄、５月龄、１０月龄、２４月龄的ＳＤ大鼠的行为学进行比较。方法：采用水迷宫及旷场分析法对上述五种不同年龄组的大鼠进行研究,数据采用多因素方差分析处理。结果：幼鼠（２２日龄、１月龄）及老年鼠（２４月龄）游泳所用时间及错误次数比成年鼠（５月龄、１０月龄）多,差异显著（Ｐ＜０．０５）。幼鼠及老年鼠的空间认知能力显著低于成年鼠,并且对新异环境的适应性差,更加紧张（Ｐ＜０．０５）。结论：动物的学习记忆能力,空间认知能力及兴奋性存在着年龄上的差异,青壮年大鼠学习记忆能力及对新异环境的适应性均强于幼年及老年大鼠     

卡麦角林处理哺乳期小鼠对子代存活和生长的影响

哺乳期是兽类繁殖成功的关键阶段之一,本实验以不同浓度卡麦角林油溶液对哺乳早期雌性小鼠连续灌胃3 d,检测雌性小鼠体重和幼鼠存活及体重变化,以此确定卡麦角林对哺乳雌性小鼠繁殖成功的影响。结果发现,卡麦角林对雌性小鼠在哺乳期的体重相对增长率无显著影响,但处理组幼鼠出现部分死亡,0 μg / kg、50 μg / kg、100 μg/ kg、200 μg/ kg、400 μg/ kg 组幼鼠死亡率分别为1.30% 、3.85% 、4. 08% 、7.38% 、21.19% ,幼鼠死亡数和剂量呈正相关,400 μg / kg 组幼鼠成活率显著下降到78 8% ,其他剂量组幼鼠成活率与对照组差异不显著;给药后7 d 存活幼鼠的生长发育显著被抑制,之后处理组幼鼠体重变化与对照组无显著差异。上述结果表明卡麦角林处理哺乳早期雌性小鼠可降低幼鼠成活率并抑制存活幼鼠的生长发育,进而有可能降低雌性小鼠及其子代的繁殖成功率。     

大鼠成年前异常生活环境对其成年后恐惧记忆的影响(英文）

为了探讨早期饲养环境对成年后大鼠条件化恐惧的影响,实验采用巴氏恐惧条件化的方法对不同饲养环境下的大鼠进行了行为检测。具体操作为：把断奶后的大鼠饲养在3个不同的人工控制的环境中（丰富环境、社群环境和贫瘠环境）;8周后进行恐惧条件化训练和测试（指标为僵直百分比）,以及检测不同饲养环境下的大鼠的体重、自发活动和足部电击敏感性。结果显示：与社群组相比,丰富组的大鼠条件化僵直水平明显增加,而贫瘠组的明显减少;丰富和贫瘠环境明显的影响了大鼠的体重;不同环境对自发活动和足部电击敏感性没有影响。这些结果说明幼年期的丰富环境能提高成年后大鼠的由声音诱发的条件化恐惧反应,而贫瘠环境则削弱了这种反应。     

大鼠成年前异常生活环境对其成年后恐惧记忆的影响

为了探讨早期饲养环境对成年后大鼠条件化恐惧的影响,实验采用巴氏恐惧条件化的方法对不同饲养环境下的大鼠进行了行为检测.具体操作为:把断奶后的大鼠饲养在3个不同的人工控制的环境中(丰富环境、社群环境和贫瘠环境);8周后进行恐惧条件化训练和测试(指标为僵直百分比),以及检测不同饲养环境下的大鼠的体重、自发活动和足部电击敏感性.结果显示:与社群组相比,丰富组的大鼠条件化僵直水平明显增加,而贫瘠组的明显减少;丰富和贫瘠环境明显的影响了大鼠的体重;不同环境对自发活动和足部电击敏感性没有影响.这些结果说明幼年期的丰富环境能提高成年后大鼠的由声音诱发的条件化恐惧反应,而贫瘠环境则削弱了这种反应.     

幼小鼠对种内几种化学信息的识别和反应

50年代以来,国际上相继开展了一些关于化学信息在小家鼠繁殖中作用的研究,并在实验室中揭示了一些反应:如集群雌鼠气味使雌鼠性周期延长的Lee-Boot效应,雌鼠气味能解除集群雌鼠对性周期的抑制、并促使它们同期发情的Whitten效应,以及陌生雄鼠气味中断妊娠的Bruce效应等等。但是,在成鼠间起作用的几种化学信息,是否能被幼鼠感受,对幼鼠的发育和性成熟是否产生影响,还是一个未知的问题。 影响小鼠发育的因素很多,除环境因子外,近来还出现了有关社群因素中外激素对小鼠性成熟影响的报道,发现雄鼠或给予雄激素的雌鼠有促进幼雌鼠性成熟的作用,范志勤发现父本气味和陌生雄鼠气味对幼雌鼠性成熟均有促进作用。但是,目前关于种内雌鼠气味、集群雌鼠气味、幼鼠气味影响性成熟的研究尚不多见。有关各种气味对性成熟效应的比较的报道亦少。本文的目的在于通过实验方法,阐明种内的几种化学信息,诸如父本、陌生雄性、雌性、集群雌性、幼雌等几种气味,对幼雌小鼠性成熟的影响,并据此了解幼鼠识别这几种信息的能力。     

不同等级环境对大、小鼠及其应用的影响

目的了解不同等级环境（屏障环境和普通环境）对实验大小鼠的一般生理表现和抗应激能力以及对药物反应的影响,初步判定严格的微生物控制是否影响实验动物的人类模型作用。方法将40只SPF级Wistar大鼠和200只SPF级BALB／c小鼠分别饲养于屏障环境和普通环境内,通过以下实验对比观察不同等级环境对实验大、小鼠及其应用的影响：每周测量动物的体重增长情况;饲养35d后,测定大鼠15项血液学指标、14项血液生化指标和9个脏器的相对重量;以抗缺氧实验和游泳实验判断对小鼠体质和抗应激能力的影响;以5．氟尿嘧啶急性毒性实验和戊巴比妥钠麻醉实验测试其对药物作用的异同。结果在5周观察期内,屏障环境饲养小鼠和大鼠的体重增长均明显快于普通环境的对照动物（P〈0．05）;普通环境饲养大鼠的血液RBC、WBC、PCT、PLT、GOT、GGT、GPT、CK、TB值高于屏障环境大鼠（P〈0．05）,而CHO、LDL-C和HDL-C值低于屏障环境大鼠（P〈0．05）;不同微生物环境条件饲养小鼠的游泳耐力和抗缺氧实验结果接近,但是屏障环境组动物所获数据的变异较小;不同等级环境条件饲养小鼠的戊巴比妥钠麻醉反应和5-氟尿嘧啶中毒反应相似,而屏障环境组动物的麻醉维持时间较短,LD50较低,95％可信限狭窄。结论饲养于屏障环境和普通环境的实验大、小鼠在一般生理表现上出现部分差异,动物的抗应激能力和对药物的反应未发生显著变化;在屏障环境条件中,动物的药物反应更敏感、所获数据更稳定,因此,初步认为严格微生物控制条件下的SPF级动物可以作为生活在自然环境中的人类的模型动物。     

夹竹桃麻素对双酚a诱导的成年雄性小鼠精子损伤作用的实验研究

目的:研究NADPH氧化酶抑制剂夹竹桃麻素(Apocynin)对双酚a(Bisphenol a,BPA)诱导的成年雄性小鼠精子损伤过程中的作用。方法:成年雄性小鼠给以BPA刺激,给以Apocynin(1 mg/kg/day和10 mg/kg/day,分别处理7 day)进行治疗,观察其对BPA诱导的成年雄性小鼠精子损伤的作用。结果:BPA处理组小鼠附睾精子数目和活力明显降低,血清中睾酮和黄体生成素水平明显减少;Apocynin治疗明显增加BPA处理组小鼠附睾中精子数目和活力,但是对血清中睾酮和黄体生成素水平没有明显影响。另外,BPA处理组小鼠睾丸中丙二醛(Malonaldehyde,MDA)水平明显增加;Apocynin治疗明显抑制了BPA处理组小鼠睾丸中MDA水平。结论:NADPH氧化酶抑制剂Apocynin减轻BPA诱导的成年雄性小鼠精子损伤。     

蓖麻油不皂化物雌激素效应及其抗生育活性相关性研究

为了探讨蓖麻油不皂化物是否具有激素效应,以及蓖麻油不皂化物与蓖麻油的抗生育活性的关联性,分别用剂量为100 mg/kg·d、 200 mg/kg·d、 500 mg/kg·d的蓖麻油不皂化物灌胃小鼠来检测其抗生育活性,并通过幼鼠子宫实验和E-SCREEN实验来检测蓖麻油不皂化物是否具有雌激素效应.结果 表明:蓖麻油不皂化物对成年小鼠具有明显的抗生育效果.在未成熟小鼠子宫实验中,当灌胃剂量为500 mg/kg·d时,表现出明显的雌激素效应;但是E-SCREEN实验结果中,蓖麻油不皂化物却未表现出雌激素效应.结论 :虽然在E-SCREEN实验中蓖麻油不皂化物不表现出雌激素效应,但是在动物个体实验中,其表现出的雌激素样作用同其抗生育作用具有一定的联系性.     

科研快讯

<正>《自然-神经科学》:催产素或可提升新生小鼠大脑感官在感官丧失后,新生小鼠大脑在感官反应方面所产生的变化可通过调控催产素得到克服。《自然-神经科学》发表的这项研究结论或能够为特定神经发育障碍比如自闭症谱系障碍(ASD)等提供治疗方法。催产素是荷尔蒙的一种,由大脑释放,能够促进性兴奋、社交和情感行为。Xiang Yu等人发现当新生小鼠在刚出生就被剥夺视觉和触觉感官时,其大脑下丘脑所产生的催产素的释放量会有所减少。剥夺幼鼠的一种感官信息也会影响其大脑中其他的感官皮层并导致这些皮层之间的兴     

Discrimination of Infant Isolation Calls by Female Greater Spear-Nosed Bats, Phyllostomus hastatus

In colonial species, recognition of offspring should be under strong selection. For accurate identification to occur offspring must emit individually distinctive signals and parents must be able to discriminate between signals. Female greater spear-nosed bats (Phyllostomus hastatus) roost in stable social groups and use infant vocalizations, termed isolation calls, to locate and identify their young. In this study, we investigate both the production and perception of isolation calls in P. hastatus. First, we measured acoustic features and found that after controlling for ontogenetic effects, sufficient variation exists between pups for isolation calls to function as individual signatures. Moreover, pups from the same social group emit calls with more similar spectral and spectro-temporal features than pups from different social groups, indicating that these features are likely heritable. We used psychoacoustic experiments in the laboratory to determine if adult females could discriminate between calls from pups in the same or different social group. Females discriminated between pups when faced with a template-matching task and their performance was correlated with the salience of spectral and spectro-temporal features. We found no difference in performance when females had to discriminate between pups from the same and different social groups. These results indicate that females should be able to accurately identify their young using isolation calls.     

Do pup ultrasonic cries provoke prolactin secretion in lactating rats?

Marked prolactin (PRL) secretion in response to the ultrasonic distress vocalizations of rat pups in lactating dams deprived of their pups for 6 hr was reported by others. In two experiments, this phenomenon could not be confirmed under our testing conditions at either 1 or 2 weeks postpartum, although behavioral responses to the ultrasounds were noted. In addition, suckling-induced PRL secretion did not differ consistently as a function of the tape recording (pup ultrasounds, 45 kHz artificially produced ultrasounds, or blank tape) heard prior to the return of pups. The functional significance of rat pup ultrasounds is considered.     

Ultrasonic Communication in Rats: Can Playback of 50-kHz Calls Induce Approach Behavior?

Rats emit distinct types of ultrasonic vocalizations, which differ depending on age, the subject's current state and environmental factors. Since it was shown that 50-kHz calls can serve as indices of the animal's positive subjective state, they have received increasing experimental attention, and have successfully been used to study neurobiological mechanisms of positive affect. However, it is likely that such calls do not only reflect a positive affective state, but that they also serve a communicative purpose. Actually, rats emit the highest rates of 50-kHz calls typically during social interactions, like reproductive behavior, juvenile play and tickling. Furthermore, it was recently shown that rats emit 50-kHz calls after separation from conspecifics. The aim of the present study was to test the communicative value of such 50-kHz calls. In a first experiment, conducted in juvenile rats situated singly on a radial maze apparatus, we showed that 50-kHz calls can induce behavioral activation and approach responses, which were selective to 50-kHz signals, since presentation of 22-kHz calls, considered to be aversive or threat signals, led to behavioral inhibition. In two other experiments, we used either natural 50-kHz calls, which had been previously recorded from other rats, or artificial sine wave stimuli, which were identical to these calls with respect to peak frequency, call length and temporal appearance. These signals were presented to either juvenile (Exp. 2) or adult (Exp. 3) male rats. Our data clearly show that 50-kHz signals can induce approach behavior, an effect, which was more pronounced in juvenile rats and which was not selective to natural calls, especially in adult rats. The recipient rats also emitted some 50-kHz calls in response to call presentation, but this effect was observed only in adult subjects. Together, our data show that 50-kHz calls can serve communicative purposes, namely as a social signal, which increases the likelihood of approach in the recipient conspecific.     

Experience restores innate female preference for male ultrasonic vocalizations

Mouse models are increasingly contributing to our understanding of the neural genetics of sensory processing and memory. For example, strain differences have helped elucidate basic mechanisms of age‐related hearing loss and auditory fear conditioning. Assessing sensory differences arising in acoustic communication contexts is also important for understanding natural audition. While this topic has not been well studied, it is currently being addressed through auditory neuroethological studies in the CBA/CaJ strain, where insights will help lay a foundation for future neural genetic studies. Here, we focus on the responses of adult females to ultrasonic vocalizations of males. We tested a group of female mice in a place‐preference paradigm before and after auditory and olfactory experience with a male. A control group was housed with other female cagemates between trials. All females showed an initial preference for male calls that rapidly decayed over the course of a trial. However, only females that had been pair‐housed with a male during the inter‐trial interval displayed a reinstated interest in male vocalizations, suggesting possible group differences in the assessment of the calls' behavioral relevance. These findings provide a timeframe during which auditory processing of male ultrasounds might be expected to show a difference depending on behavioral relevance, and also suggest an importance of social interactions in maintaining call recognition.     

Comparative study on isolation calls emitted from hamster pups.

Waveforms of isolation calls emitted from hamster pups, which were Syrian hamsters, Djungarian hamsters, and Chinese hamsters, were compared in a basic study on improving reproduction by decrease of cannibalism, because it was reported that maternal behavior was induced by isolation calls in rodents. Isolation calls of hamster pups, isolated from their mother and receiving cold stress, were collected by Real-Time Spectrogram (RTS), and calculated to spectrograms and power spectra by SIGNAL. Isolation calls consisted of ultrasonic vocalizations (USVs) and audible vocalizations (ADVs) in each species. Waveforms of isolation calls emitted by the hamster pups, were shown to have several characteristic features. In this study, the species specificity of isolation calls was shown in hamster pups. It would seem that the species specificity originates in the differences of sensitivity to cold stress via the autonomic nerve in hamsters.     

Context-related vocalizations in African grey parrots (Psittacus erithacus)

A few animal species are capable of vocal learning. Parrots are well known for their vocal imitation abilities. In this study, we investigated whether African grey parrots (Psittacus erithacus) emit specific vocalizations in specific contexts. We first described the vocal repertoire and its ontogenesis of four captive grey parrots. After a comparison with vocalizations emitted by wild and other captive African grey parrots, we observed that only three call categories were shared by all grey parrots populations, suggesting that isolated populations of parrots develop population-specific calls. Then, we artificially provoked ten different contexts and recorded vocalizations of four captive grey parrots in these situations. Parrots predominantly emitted call categories in some contexts: distress, protestation, alarm, asking (i.e. emitted when a bird wanted something from an experimenter) and contact calls. These results suggest that some calls are learned and can be used in specific contexts.     

Ultrasonic Reaction of Bank Vole Males to the Presence of Females Varying in Hormonal Activity

Rodents are known to emit ultrasounds during social interactions. Despite the evidence that ultrasonic vocalizations are emitted during sexual encounters and may play a certain role in sexual selection, only a few studies have investigated this phenomenon, mainly in laboratory rodents. We analysed the ultrasonic calls of bank vole (Myodes glareolus) males from an outbred colony in the presence of females differing in hormonal activity. Sexually experienced males were tested during interactions with naive, ovariectomized, pregnant and post‐partum oestrous females. We found that the males’ ultrasound vocalizations depend on the phase of the bank vole females’ reproductive cycle. During encounters with post‐partum oestrous females the males emitted significantly more ultrasounds, and the total duration of ultrasound vocalization was longer. The presence of post‐partum oestrous females also influenced the type of ultrasounds: the most typical constant‐frequency sounds were significantly shorter, and two additional types of ultrasounds were presented during interactions with females ready to mate: U‐shaped frequency‐modulated sounds and frequency‐modulated upsweep sounds. To our knowledge this is the first evidence that male voles of the subfamily Arvicolinae emit different types of ultrasounds in the presence of females depending on their reproductive stage. We suggest that these ultrasounds may be employed as an attractant during reproductive behaviour and that they are potentially an element of sexual selection.     

Adult male mice emit context-specific ultrasonic vocalizations that are modulated by prior isolation or group rearing environment

Social interactions in mice are frequently analysed in genetically modified strains in order to get insight of disorders affecting social interactions such as autism spectrum disorders. Different types of social interactions have been described, mostly between females and pups, and between adult males and females. However, we recently showed that social interactions between adult males could also encompass cognitive and motivational features. During social interactions, rodents emit ultrasonic vocalizations (USVs), but it remains unknown if call types are differently used depending of the context and if they are correlated with motivational state. Here, we recorded the calls of adult C57BL/6J male mice in various behavioral conditions, such as social interaction, novelty exploration and restraint stress. We introduced a modulator for the motivational state by comparing males maintained in isolation and males maintained in groups before the experiments. Male mice uttered USVs in all social and non-social situations, and even in a stressful restraint context. They nevertheless emitted the most important number of calls with the largest diversity of call types in social interactions, particularly when showing a high motivation for social contact. For mice maintained in social isolation, the number of calls recorded was positively correlated with the duration of social contacts, and most calls were uttered during contacts between the two mice. This correlation was not observed in mice maintained in groups. These results open the way for a deeper understanding and characterization of acoustic signals associated with social interactions. They can also help evaluating the role of motivational states in the emission of acoustic signals.     

Singing in the Face of Danger: the Anomalous Type II Vocalization of the Splendid Fairy-Wren

Males of certain species of fairy-wrens (Aves: Maluridae) emit a unique vocalization, the Type II vocalization, in response to the calls of potential predators. We conducted field observations and playback experiments to identify the contexts in which the Type II vocalization is emitted by splendid fairy-wren ( Malurus splendens ) males, and to examine social and genetic factors that influence its occurrence. In field observations and controlled playback experiments, Type II vocalizations were elicited most consistently by calls of the predatory gray butcherbird ( Cracticus torquatus ). Some vocalizations from other avian species also elicited Type II vocalizations, and the majority of these were vocalizations from avian predators. Splendid fairy-wrens are cooperative breeders, and males that responded with Type II vocalizations to playbacks of butcherbird calls tended to be primary rather than secondary males, had larger cloacal protuberances, and were older than those that did not respond. In addition, secondary males that were sons of resident females were more likely than non-sons to respond with a Type II vocalization. In another playback experiment, females responded similarly to the Type I song and Type II vocalizations of their mates. Although the Type II vocalization is emitted primarily in response to predator calls, it is inconsistent with an alarm call explanation. Patterns of reproductive success among Type II calling males suggest that it does not function as an honest signal of male quality. At present, the function of the vocalization remains anomalous, but indirect fitness benefits may play a role in its explanation.     

Olfactory and Thermal Influences on Ultrasonic Vocalization During Development in Rodents

Ultrasounds are emitted by developing rodents, and changes withage in several parameters of vocalization have been reportedfor numerous myomorphs. In this paper I integrate with ultrasonicvocalization several behaviors which change during development.Included are studies controlling stimulation by olfactory, thermal,and tactile cues as well as detailed studies of specific responsessuch as movement, suckling, grooming, and huddling. Developmentis analyzed in well-known species, such as the rat (Rattus norvegicus),and in less familiar species, especially the pine vole (Microtuspinetorum). Lacking the capacity for physiological thermoregulation, altricialrodent pups with their mother use several behavioral strategieswhich facilitate thermoregulation. Inside the nest, pups adjustthe temperature by changing their huddling. The mother regulatesthe length of suckling bouts according to her body temperature.When a pup is removed from the warm nest, vocalizations of thepup can increase the likelihood of retrieval by the mother andthereby indirectly facilitate thermoregulation. In several species which have been studied, vocalization ratesare highest when pups begin to move into and out of nests andexhibit olfactory-directed movement. As olfactory preferencesbecome established and movement is coordinated, a decline invocalization appears in rat, mouse, hamster, spiny mouse, andpine vole. In the gerbil, however, the decline precedes competencein olfactory-directed movement. In the presence of home shavings, young rats emit low ratesof vocalization, while pine vole young emit calls at a highrate. This contrast may relate to the intensive attachment ofyoung pine voles to the mother in early life.