Identification of alpha-2u globulin in the rat preputial gland by MALDI-TOF analysis

The low molecular mass proteins found in the pheromonal sources such as urine, saliva, glandular secretion etc have been reported as ligand carriers for the processes of chemocommunication in mammals. The preputial gland plays an important role in the production of olfactory signals for pheromonal communication. Thus, in the present study, alpha-2u globulin having molecular mass of 18 kDa has been identified in the preputial gland of Norway rat (Rattus norvegicus) by in-gel trypsin digestion and analyzing the resulting peptides by MALDI-TOF. Since preputial gland is one of the major pheromonal sources in rat, the results suggest that alpha-2u globulin might act as a carrier for hydrophobic odorants of preputial gland.     

Olfaction and olfactory-mediated behaviour in psychiatric disease models

Rats and mice are the most widely used species for modelling psychiatric disease. Assessment of these rodent models typically involves the analysis of aberrant behaviour with behavioural interactions often being manipulated to generate the model. Rodents rely heavily on their excellent sense of smell and almost all their social interactions have a strong olfactory component. Therefore, experimental paradigms that exploit these olfactory-mediated behaviours are among the most robust available and are highly prevalent in psychiatric disease research. These include tests of aggression and maternal instinct, foraging, olfactory memory and habituation and the establishment of social hierarchies. An appreciation of the way that rodents regulate these behaviours in an ethological context can assist experimenters to generate better data from their models and to avoid common pitfalls. We describe some of the more commonly used behavioural paradigms from a rodent olfactory perspective and discuss their application in existing models of psychiatric disease. We introduce the four olfactory subsystems that integrate to mediate the behavioural responses and the types of sensory cue that promote them and discuss their control and practical implementation to improve experimental outcomes. In addition, because smell is critical for normal behaviour in rodents and yet olfactory dysfunction is often associated with neuropsychiatric disease, we introduce some tests for olfactory function that can be applied to rodent models of psychiatric disorders as part of behavioural analysis.     

两种兔尾鼠的化学信息及其在群体中的作用

黄兔尾鼠(Lagurus lutens)及草原兔尾鼠(Lagurus lagurus)是新疆某些地区主要害鼠之一,它们的繁殖能力很强,数量高峰时,对草场危害极大。此外,它们还能传染某些地方性流行病,所以对这两种害鼠的防治是十分必要的。 近年来,我们在研究动物化学通讯的过程中,了解到外激素(信息素)在动物间传递信     

The sensory basis of olfactory search behavior in banded kokopu (<Emphasis Type="Italic">Galaxias fasciatus</Emphasis>)

The sensory basis of olfactory search behavior was investigated in the banded kokopu, Galaxias fasciatus, using a flow tank. In the presence of a 2 cm s(-1) current flow, banded kokopu use both water current and chemical information to locate a food odor source. The superficial neuromasts of the lateral line system mediate the rheotactic component of the odor search. A physical block of one olfactory nostril did not affect the olfactory search strategy employed by banded kokopu in still water or in the presence of a current flow. Thus, there is no evidence that banded kokopu perform a bilateral comparison of the olfactory stimulus during their odor search. Previously, olfaction and gustation have been the only sensory systems shown to directly mediate orientation and movement towards odor sources in fish. The use of hydrodynamic cues by fish in location of an olfactory source has been previously proposed, but without direct experimental identification of the sensory systems employed. This study identifies the contributing roles of both olfactory and hydrodynamic sensory systems to the olfactory search repertoire of fish.     

Processing by the main olfactory system of chemosignals that facilitate mammalian reproduction

This article is part of a Special Issue “Chemosignals and Reproduction”.Most mammalian species possess two parallel circuits that process olfactory information. One of these circuits, the accessory system, originates with sensory neurons in the vomeronasal organ (VNO). This system has long been known to detect non-volatile pheromonal odorants from conspecifics that influence numerous aspects of social communication, including sexual attraction and mating as well as the release of luteinizing hormone from the pituitary gland. A second circuit, the main olfactory system, originates with sensory neurons in the main olfactory epithelium (MOE). This system detects a wide range of non-pheromonal odors relevant to survival (e.g., food and predator odors). Over the past decade evidence has accrued showing that the main olfactory system also detects a range of volatile odorants that function as pheromones to facilitate mate recognition and activate the hypothalamic-pituitary-gonadal neuroendocrine axis. We review early studies as well as the new literature supporting the view that the main olfactory system processes a variety of different pheromonal cues that facilitate mammalian reproduction.     

Eliciting Play: A Comparative Study: (Octodon, Octodontomys, Pediolagus, Phoca, Chocropsis, Ailuropoda)

The social play behavior of six mammalian species (Rodentia,Pinnipedia, Artiodactyla, Carnivora) is described and compared.Locomotor and Rotational Movements, e.g., jumping, running,and headshaking, occurred in all species and predominated inthe rodent play. These movements are similar in form to anti-predatorand "protective" responses and result in an immediate but temporarycessation of sensory stimulation from conspecifics. Investigation of body odors was the most important stimuluseliciting Locomotor-Rotational Movements in the rodents. Inthe larger mammals, body odor sniffing was enhanced during play,but specialized signals from other sensory modalities elicitedand maintained play interactions. The possible functions ofa heightened exchange of olfactory information during juvenilesocial development are discussed.     

Identification of sex-associated protein in the preputial gland of house rat (a new insight in rodent pest management)

Our recent findings revealed that the preputial gland of male house rat contains 20 kDa protein, however, the role of androgen in the production of this protein is not known. Hence, the present study was carried out to evaluate the androgen dependency of 20 kDa protein in the preputial gland of house rat (Rattus rattus) and to compare its presence in female clitoral gland. Further, on castration the amount of glandular protein in male was significantly decreased to a certain extent, while testosterone treatment on castrated males showed an increasing trend. The electrophorogram of male house rat showed six different protein fractions with molecular weights of 90, 70, 60, 50, 35 and 20 kDa. However, the 70, 60, 50 and 35 kDa were absent in female. Among the different fractions, 90 and 20 kDa proteins were prominent. On castration, the 20 kDa protein was disappeared; while on testosterone treatment the protein reappeared. Thus, the present study concludes that the 20 kDa protein is a testosterone dependent sex-associated protein. Since urinary protein is found to act as carrier for volatile substances in pheromonal communication. The present study suggests that the glandular protein may bind with the volatile compounds produced from preputial gland. Identification of this carrier protein in the preputial gland explores the possibility of developing pheromonal trap for rodent pest management (RPM).     

Identification of glandular (preputial and clitoral) proteins in house rat (Rattus rattus) involved in pheromonal communication

Proteins (18-20 kDa) belonging to lipocalin family have been reported to act as carriers for ligands binding to pheromones in mouse urine, pig saliva, hamster vaginal fluid and human sweat, that are involved in pheromonal communication. As the preputial gland is a major pheromonal source, the present study was aimed to detect the specific protein bands (around 18-20 kDa) in the preputial and clitoral glands of the house rat, R. rattus. The amount of protein was higher in preputial gland of the male than that of female (clitoral) gland. A 20 kDa protein was noted in male and female glands; however, the intensity of the band was much higher in male than in female. In addition, 70, 60, 35 kDa bands, identified in male preputial gland, were absent in females. The presence of higher concentration of glandular proteins in the male preputial gland suggests that male rats may depend more on these glandular proteins for the maintenance of reproductive and dominance behaviours. The results further suggest that these glandular proteins (20 kDa) may act as a carrier for ligand binding.     

Sex- and strain-specific expression and vomeronasal activity of mouse ESP family peptides

Male mice secrete exocrine-gland-secreting peptide 1 (ESP1) from the extraorbital lacrimal gland into tear fluid [1]. Other mice detect ESP1 through sensory neurons in the vomeronasal organ (VNO), a secondary olfactory system that senses pheromonal information, including sex, strain, and species. ESP1 is now known to be a member of a multigene family that encodes peptides of various lengths. We herein performed genomic and expression analyses of the ESP family. The ESP family consists of 38 members in mice and 10 members in rat but is absent from the human genome, suggesting rapid molecular evolution. In addition to the male-specific ESP1, we discovered one, which we designated ESP36, that, in adult BALB/c mice, is expressed only in the female extraorbital lacrimal gland. The sexually dimorphic expression is ensured by the release of testosterone after puberty. However, we observed dramatic differences in the expression levels of ESPs between strains. Finally, all ESPs elicited an electrical response in the vomeronasal epithelium but not in the main olfactory epithelium. Multielectrode recording of VNO activity demonstrated that ESP1 induces action potentials in vomeronasal neurons, leading to an increase in the spike firing rate, and that ESP1 is recognized by narrowly tuned vomeronasal sensory neurons. Sexual dimorphism and strain differences of ESPs and their reception in the VNO suggest that the ESP family can convey information about sex and individual identity via the vomeronasal system. The chemosensation of this nonvolatile peptide family by direct contact appears to be one of strategies for sociosexual communication in rodent species.     

The role of uropygial gland on sexual behavior in domestic chicken Gallus gallus domesticus

Recent studies have indicated that avian social behavior is influenced by olfactory cues. During the reproductive season a change in the chemical composition of uropygial gland secretion has been reported in some species and the hypothesis that olfactory signals may be produced by this gland has been proposed. To examine this hypothesis we performed two behavioral experiments to determine whether a female’s uropygial gland produce chemical signals that stimulate mating behaviors in domestic chickens. In Experiment 1 the role of the female’s uropygial gland in male mating behavior was examined by removing and examining the female’s uropygial gland. The frequency of mounts and copulations of intact male birds with sham-operated female birds was significantly higher than with uropygial glandectomized female birds. With respect to the number of waltzing that is one of the courtship displays intact males showed no significant difference between sham-operated female birds and uropygial glandectomized female birds. In Experiment 2 the relationship between male olfaction and the female’s uropygial gland was investigated using olfactory bulbectomized male birds. The number of mounts and copulations of sham-operated male birds with sham-operated female bird was significantly higher than with uropygial glandectomized female birds. In contrast olfactory bulbectomized male birds showed no significant differences in the number of mounts and copulations between sham-operated female birds and uropygial glandectomized female birds. These results indicate that intact and sham-operated male birds prefer to mate with female birds with the uropygial gland. The number of courtship waltzing of sham-operated male birds showed no significant difference. However olfactory bulbectomized male birds significantly courted to uropygial glandectomized female birds. Summarizing our results show that while anosmic males did not have any preference both intact and sham-operated male birds chose to mate with female birds having an intact uropygial gland suggesting that mate preference involves in male olfaction and that the female’s uropygial gland acts as a source of social odor cues in domestic chickens.     

啮齿动物的嗅觉通讯研究进展

通过对近40 年来啮齿动物嗅觉通讯的研究综述, 主要介绍嗅觉信号的来源、组成及其对啮齿动物行为生理所产生的作用。啮齿动物嗅觉通讯的信号来源主要是粪便、尿液和特化皮肤腺等, 对这些化学信号的成分分析主要集中在各种信息素(Pheromone) 的结构、来源及其引起的行为反应。目前, 在对啮齿动物嗅觉通讯神经通路的研究中, 对主嗅觉系统和犁鼻器系统在动物嗅觉通讯中的作用仍将是人们研究的重点; 而通过信息素作用所产生的各种行为反应的神经内分泌机制也是动物嗅觉通讯领域研究的热点之一。研究气味信号对动物行为和生理等方面所产生的作用, 将有助于揭示啮齿动物嗅觉通讯在其社会行为中的重要作用。     

扬子鳄鼻腔上皮光学显微镜及扫描电镜观察

本文通过光镜和扫描电镜研究了爬行动物扬子鳄鼻腔上皮的组织学。结果表明:其嗅觉上皮的组成细胞类型与两栖类、鸟类和哺乳类基本相似,但嗅细胞纤毛形状则有所不同;扬子鳄与两栖类、鸟类嗅纤毛相似,呈丝状,而哺乳类嗅觉纤毛则呈棍棒状;据外,扬子鳄鼻腔不同部位可发现不同类型嗅纤毛,鸟兽则无此现象,扬子鳄嗅觉上皮的分布仅局限于鼻腔中部前甲区和鼻甲区狭小范围,而兽类嗅觉上皮一般分布较广;扬子鳄呼吸上皮下未见兽类具有的混合型粘液腺,也未见兽类用以温暖空气的静脉丛,这和扬子鳄属外温动物而兽类为恒温动物密切相关。     

Olfactory Communication and Neighbor Recognition in Giant Kangaroo Rats

We hypothesized that olfactory communication facilitates neighbor recognition in the giant kangaroo rat, Dipodomys ingens , and is therefore influential in coordinating social interactions in this solitary, desert rodent. We tested whether (i) D. ingens can discriminate between odors of same- and opposite-sex conspecifics; and (ii) the kangaroo rats exhibit scent preferences based on familiarity. In habituation-discrimination tests, we found that both genders distinguish differences between the scent of individuals of the same- and opposite-sex. In olfactory preference tests, both males and females spent significantly more time investigating the scent of their familiar cagemate than the scent of an unfamiliar conspecific. Giant kangaroo rats may be able to recognize familiar neighbors from olfactory cues, thus supporting a hypothesis of neighbor recognition. Neighbor recognition may be an important mechanism of social interactions in this endangered species.     

The source of an aggression-promoting olfactory cue,released by α-Melanocyte stimulating hormone,in the male mouse

Earlier experiments demonstrated that the injection of α-melanocyte stimulating hormone into one mouse of a male pair results, 15 minutes later, in the release of an olfactory cue which increases the aggressive behavior of its partner. Because the preputial gland, whose activity is dependent upon testosterone and α-MSH, produces an odor which stimulates aggressive behavior, its relationship with the MSH response was investigated. Preputialectomy failed to prevent the release of the odor by an MSH-treated subordinate mouse of a pair, although preputialectomy of one mouse of a naive pair resulted in it later displaying higher levels of aggression than its intact partner, which then became subordinate. Swabs taken from the perineal region of α-MSH-injected subordinates, contained more aggression-promoting factor than swabs taken from saline injected subordinates. It is concluded that the short-term effects of α-MSH upon aggression are probably via a product of glandular or urinary origin other than the preputial gland and that the latter is more involved in long-term aggression-promoting cues.     

Information processing in mammalian olfactory system

In recent years, considerable progress has been made in understanding how the olfactory system uses neural space to encode sensory information. In this review, we focus on recent studies aimed at understanding the organizational strategies used by the mammalian olfactory system to encode information. The odorant receptor gene family is discussed in the context of its genomic organization as well as the specificity of olfactory sensory neurons. These data have important consequences for the mechanisms of odorant receptor gene choice by a given sensory neuron. Division of the olfactory epithelium into zones that express different sets of odorant receptors is the first level of input organization. The topographical relationship between periphery and olfactory bulb represents a further level of processing of information and results in the formation of a highly organized spatial map of information in the olfactory bulb. There, local circuitry refines the sensory input through various lateral interactions. Finally, the factors that may drive the development of such a spatial map are discussed. The onset of expression and the establishment of the zonal organization of odorant receptor genes in the epithelium are not dependent upon the presence of the olfactory bulb, suggesting that the functional identity of olfactory sensory neurons is determined independently of target selection. © 1996 John Wiley & Sons, Inc.     

Neuronal development: specifying a hard-wired circuit

The formation of neuronal circuits that relay distinct olfactory information is thought to depend on cues provided by pre-synaptic receptor neurons. But direct visualization of second order neurons in Drosophila now suggests that dendritic targeting occurs independently of interactions with incoming sensory neurons.     

Roles of odorant receptors in projecting axons in the mouse olfactory system

In the mouse olfactory epithelium, there are about ten million olfactory sensory neurons, each expressing a single type of odorant receptor out of approximately 1000. Olfactory sensory neurons expressing the same odorant receptor converge their axons to a specific set of glomeruli on the olfactory bulb. How odorant receptors play an instructive role in the projection of axons to the olfactory bulb has been one of the major issues of developmental neurobiology. Recent studies revealed previously overlooked roles of odorant receptor-derived cAMP signals in the axonal projection of olfactory sensory neurons; the levels of cAMP and neuronal activity appear to determine the expression levels of axon guidance/sorting molecules and thereby direct the axonal projection of olfactory sensory neurons. These findings provide new insights as to how peripheral inputs instruct neuronal circuit formation in the mammalian brain.     

在自然状态下黄毛鼠包皮腺的引诱力及季节变化

黄毛鼠(Rattus rattoides Hodgson)包皮腺成对位于下腹部的皮下,腺体开口于尿道口外包皮内的两侧。腺体形态,雌雄各异。雌性呈豆瓣形;雄性呈瓜籽形。体长150毫米以上的成年鼠,其包皮腺的长和宽约18和9毫米。包皮腺是动物的一个外激素释放源,对于种群的调节有着重要的作用(Christiansen ＆ Dving 1975)。关于它的性引诱作用见诸于Bronson ＆ Caroom(1971)、刘炳谦、刘素霞(1979)等。但在自然情况下包皮腺分泌及其引诱作用尚少报道。本文通过野外试验,初步研究了黄毛鼠包皮腺的分泌及引诱力的变化规律,探讨利用此特性的可能性。无疑,这对进一步研究外激素对种群调节作用以及鼠害防治方面是有意义的。