甘肃鼢鼠与根田鼠的犁鼻器和副嗅球结构研究

为了探讨地下鼠犁鼻系统与地面鼠的差异及其与地面鼠嗅觉功能相适应的特点,用组织学方法对甘肃鼢鼠(Myospalax cansus)与根田鼠(Microtus oeconomus)的副嗅球和犁鼻器结构并进行了差异性研究。结果表明,2种鼠的犁鼻器均位于鼻腔前端鼻中隔基部两侧,呈管状;甘肃鼢鼠犁鼻上皮厚度、副嗅球颗粒细胞和僧帽细胞带宽比根田鼠发达;甘肃鼢鼠犁鼻器、副嗅球的性二型分化比根田鼠显著。2种鼠各自犁鼻器和副嗅球的形态有一定的对应关系,甘肃鼢鼠犁鼻上皮、副嗅球厚而短;根田鼠犁鼻上皮、副嗅球薄而长。这种对应关系可能与犁鼻器和副嗅球之间存在着神经投射有关。     

中国林蛙嗅觉系统和犁鼻系统的显微结构

为了探讨两栖动物嗅器和犁鼻器在种系发生中的意义,用光学显微镜观察了中国林蛙嗅觉系统和犁鼻系统的组织结构。结果显示,嗅器可分为主嗅室、中室和下室3部分;主嗅室被覆嗅上皮,中室和下室被覆非嗅上皮。犁鼻腔位于嗅器的腹内侧,与下室相通,被覆发达的犁鼻上皮。背侧嗅神经起始于主嗅室背侧嗅上皮,经由嗅球腹外侧和前部进入同侧嗅球;犁鼻神经起始于犁鼻器上皮,经由嗅球腹正中部进入同侧副嗅球。     

Encoding pheromonal signals in the accessory olfactory bulb of behaving mice

Many mammalian species rely on pheromones-semiochemicals produced by other members of the same species-to communicate social status and reproductive readiness. To assess how the central nervous system integrates the complex repertoire of pheromones, we recorded from single neurons in the accessory olfactory bulb, a nucleus that processes pheromonal signals, of male mice engaged in natural behaviors. Neuronal firing was robustly modulated by physical contact with male and female conspecifics, with individual neurons activated selectively by specific combinations of the sex and strain of conspecifics. We infer that mammals encode social and reproductive information by integrating vomeronasal sensory activity specific to sex and genetic makeup.     

Evidence for olfactory function in utero

Pregnant rats received 2-[14C]deoxy-D-glucose (2DG) intravenously on the last day of gestation, and their fetuses were delivered 1 hour later by cesarean section. Fetal brains showed high 2DG uptake spread throughout the accessory olfactory bulb and little or no differential uptake in the main olfactory bulb. These findings demonstrate that functional activity occurs in the accessory olfactory bulb in utero and suggest that the accessory olfactory system may be the pathway by which fetal rats detect the odor quality of their intrauterine milieu.     

齐口裂腹鱼端脑形态和组织学研究

采用苏木精 -伊红、美兰染色技术对 5尾齐口裂腹鱼端脑的外部形态和组织结构进行了研究。观察发现 ,齐口裂腹鱼的端脑发达 ,由嗅球、嗅茎和左右端脑半球构成。嗅球位于嗅窝内 ,嗅囊的后方 ,以嗅茎与后面的左右端脑半球联系。嗅球的组织结构成层状结构 ,从外向内依次为上皮、神经纤维层和小细胞层。端脑半球外部被有原脑皮 ,两者之间的腔隙为脑室 ,其内的纹状体被横行和纵行的沟分成若干小叶。神经核分布于纹状体的周缘 ,主要有连前核、背嗅核、侧嗅核、视前核、梨状核、侧连核和脚内核等。本文对纹状体内各核的特征进行观察和描述。     

Olfactory input to the hypothalamus: electrophysiological evidence

Electrical stimulation of the rat's olfactory bulb or lateral olfactory tract elicited unit discharges in the region of the medial forebrain bundle of the lateral hypothalamus, with latencies of 4 to 25 milliseconds. Unit responses in this area were driven by odors in preparations that were paralyzed to prevent breathing artifacts.     

Olfactory recognition: a simple memory system

Mice have an olfactory (pheromone) recognition memory located at the first relay in the sensory system. It is acquired with one-trial learning, contingent upon norepinephrine activation at mating, and lasts for several weeks. The mechanism involves Hebbian (association-dependent) changes in synaptic efficacy at dendrodendritic synapses in the accessory olfactory bulb. As a result of this memory, males made familiar by mating are recognized by the females, thereby mitigating pregnancy block. Such a memory function is biologically important to the female, as it is required to sustain pregnancy in the presence of her stud male's odors.     

Combinatorial effects of odorant mixes in olfactory cortex

In mammals, each odorant is detected by a combination of different odorant receptors. Signals from different types of receptors are segregated in the nose and the olfactory bulb, but appear to be combined in individual neurons in the olfactory cortex. Here, we report that binary odorant mixes stimulate cortical neurons that are not stimulated by their individual component odorants. We propose that cortical neurons require combinations of receptor inputs for activation and that merging the receptor codes of two odorants provides novel combinations of receptor inputs that stimulate neurons beyond those activated by the single odorants. These findings may explain why odorant mixtures can elicit novel odor percepts in humans.     

Norepinephrine in chronic paranoid schizophrenia: above-normal levels in limbic forebrain

In postmortem examination of brains of four patients with chronic paranoid schizophrenia, above-normal norepinephrine levels were measured in the ventral septum, the bed nucleus of the stria terminalis, the nucleus accumbens, and the mammillary bodies. No changes were detected in other limbic forebrain regions, including the hypothalamus and the medial olfactory (preoptic) area. The results point to the possibility of a malfunction of limbic noradrenergic mechanisms in schizophrenia, especially the paranoid variety.     

驴下橄榄复合体的特征

本研究结果表明,驴下橄榄复合体由主核、两个副核和三个细胞柱组成,平均长度14.4mm。主核呈囊状,囊壁皱襞少而小,囊底不弯曲;内侧副核有6个多变的组成部,以“八”字形B核为特殊;背侧副核结构松散;三个细胞柱未见报道,暂名:下橄榄背板背侧细胞柱、下橄榄腹内侧细胞柱和下橄榄底细胞柱。主核和两个副核主要成自中等卵圆形细胞,它们占细胞总数的89.8％,其余为小细胞。三个特殊细胞柱除含中、小细胞外,还有13.1～58.5％的大细胞。     

中华蟾蜍胚后嗅球神经元自发电活动的发育变化

[目的]探讨中华蟾蜍(Bufo bufo gargarizans)胚后嗅球神经元自发电活的电生理学特性的发育变化。[方法]应用微电极电生理技术,对中华蟾蜍胚后嗅球神经元的自发放电活动进行在体胞外记录。[结果]随着嗅球的发育,其神经元的放电形式逐渐增多,单个放电振幅逐渐增大,且在变态期达最大;连续放电振幅在胚后发育的中期变化不大,但高于发育的早期和成体期;连续簇状放电频率随着发育时期而降低,但在成体期再次升高,而连续单个放电频率只在成体期增大。[结论]随着嗅球的发育,神经元的兴奋性逐步提高,神经元电活动形式逐渐呈现多样化。     

草鱼嗅觉有关器官形态结构的初步观察

本文对草鱼嗅觉有关器官—嗅囊、嗅板、嗅球和嗅茎的形态结构进行了观察,并对鲤鱼的上述器官的结构作了对比观察。     

电针迎香穴对嗅觉功能障碍大鼠胰岛素样生长因子-1的影响

目的 探讨电针迎香穴对嗅觉功能障碍大鼠胰岛素样生长因子-1（insulin-like growth factor 1,IGF-1）的影响。方法 将50只SD大鼠随机分为5组,分别是正常组、嗅觉功能障碍组、嗅觉功能障碍+眶下神经切断组、嗅觉功能障碍+电针组、嗅觉功能障碍+眶下神经切断+电针组,电针干预迎香穴后,运用嗅觉迷宫实验和对大鼠嗅球组织及血液中IGF-1进行ELISA、免疫组织化学等方法进行分析研究。结果 嗅觉功能障碍+电针组大鼠与正常组相比,其嗅觉功能明显改善（P<0.01）,其嗅球组织及血液中IGF-1表达明显升高（P<0.05）,而嗅觉功能障碍+眶下神经切断+电针组大鼠与正常组相比,其嗅觉功能和嗅球组织及血液中IGF-1表达无明显改善（P>0.05）。结论 电针迎香穴对嗅觉功能障碍模型大鼠具有显著干预效应,其作用机制可能是通过三叉神经通路,促进大鼠体内IGF-1的产生,从而有利于嗅觉系统嗅感神经元（ORN）再生,改善嗅觉功能障碍。     

Olfactory discrimination in the rabbit olfactory glomerulus

Slow potentials evoked by odor stimulation were recorded from individual glomeruli in the olfactory bulb. Systematic analysis of responses to nine different, arbitrarily selected stimuli strongly suggests a certain amount of discrimination. This fact seems to reflect in the first synapse of the olfactory tract the type of discrimination that was recently demonstrated within olfactory neuroepithelium.     

Olfactory bulb units: activity correlated with inhalation cycles and odor quality

Single olfactory bulb units were studied in two macrosmatic species of rodents under conditions intended to preserve the cyclical stimulation which normally accompanies nasal breathing. Patterns of unit activity related to the inhalation cycle were observed in all animals, often in the absence of specific stimuli, and could not be explained in simple mechanical terms. Distinctive changes in these patterns occurred in response to certain odors, and were generally independent of changes in the overall firing frequency. These findings indicate that a change in the overall firing frequency of unit discharges is neither a necessary nor sufficient measure of responsiveness to odors in the rodent olfactory bulb, and that stimulus-specific temporal distributions of unit firing may be involved in olfacto-endocrine activities.     

Experimentally induced visual projections into auditory thalamus and cortex

Retinal cells have been induced to project into the medial geniculate nucleus, the principal auditory thalamic nucleus, in newborn ferrets by reduction of targets of retinal axons in one hemisphere and creation of alternative terminal space for these fibers in the auditory thalamus. Many cells in the medial geniculate nucleus are then visually driven, have large receptive fields, and receive input from retinal ganglion cells with small somata and slow conduction velocities. Visual cells with long conduction latencies and large contralateral receptive fields can also be recorded in primary auditory cortex. Some visual cells in auditory cortex are direction selective or have oriented receptive fields that resemble those of complex cells in primary visual cortex. Thus, functional visual projections can be routed into nonvisual structures in higher mammals, suggesting that the modality of a sensory thalamic nucleus or cortical area may be specified by its inputs during development.     

MHC class I peptides as chemosensory signals in the vomeronasal organ

The mammalian vomeronasal organ detects social information about gender, status, and individuality. The molecular cues carrying this information remain largely unknown. Here, we show that small peptides that serve as ligands for major histocompatibility complex (MHC) class I molecules function also as sensory stimuli for a subset of vomeronasal sensory neurons located in the basal Gao- and V2R receptor-expressing zone of the vomeronasal epithelium. In behaving mice, the same peptides function as individuality signals underlying mate recognition in the context of pregnancy block. MHC peptides constitute a previously unknown family of chemosensory stimuli by which MHC genotypic diversity can influence social behavior.     

Recurrent excitation of secondary olfactory neurons: a possible mechanism for signal amplification

Secondary neurons of the olfactory bulb can be excited monosynaptically after activation of neighboring secondary neurons by antidromic and orthodromic volleys. Recurrent collaterals of secondary neurons are proposed to synapse with other secondary neurons, thus forming a direct recurrent excitatory pathway. Such a positive feedback system could strengthen the original input signal.     

Olfactory bulb response of rabbit

An approach to understanding the properties of dendrites is to record the response of the olfactory bulb where the dendrites of mitral cells form the glomeruli. After the stimulations of the bulb and nasal mucosa, the responses appear different, but they are fundamentally composed of three successive potentials, suggesting that the last one is the action potential of glomerular dendrites.     

Erratum

In the report "Access of urinary nonvolatiles to the mammalian vomeronasal organ" by C. J. Wysocki et al. (15 Feb., p. 781), the parts of Fig. I were inadvertently interchanged.