Dependence of olfactory bulb neurogenesis on prokineticin 2 signaling

Neurogenesis persists in the olfactory bulb (OB) of the adult mammalian brain. New interneurons are continually added to the OB from the subventricular zone (SVZ) via the rostral migratory stream (RMS). Here we show that secreted prokineticin 2 (PK2) functions as a chemoattractant for SVZ-derived neuronal progenitors. Within the OB, PK2 may also act as a detachment signal for chain-migrating progenitors arriving from the RMS. PK2 deficiency in mice leads to a marked reduction in OB size, loss of normal OB architecture, and the accumulation of neuronal progenitors in the RMS. These findings define an essential role for G protein-coupled PK2 signaling in postnatal and adult OB neurogenesis.     

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.     

Nerve growth factor gene expression in the developing rat brain

The regulation of nerve growth factor (NGF) protein and NGF messenger RNA (mRNA) in the developing rat brain has been studied to assess the hypothesis that NGF supports the differentiation of cholinergic neurons in the basal forebrain. In the adult, the major targets of these neurons, the hippocampus and neocortex, contain the highest concentrations of NGF mRNA, but comparatively low ratios of NGF protein to its mRNA. In contrast, a high concentration of NGF protein and a low concentration of NGF mRNA were seen in the basal forebrain, consistent with retrograde transport of NGF protein into this region from the neocortex and hippocampus. In these two target regions NGF and NGF mRNA were barely detectable at birth, their concentrations increased to a peak at day 21, and then NGF mRNA, but not NGF protein, declined threefold by day 35. NGF accumulation in the basal forebrain paralleled that in the target regions and preceded an increase in choline acetyltransferase, suggesting that the differentiation of cholinergic projection neurons is indeed regulated by retrogradely transported NGF. In addition, high ratios of NGF protein to NGF mRNA, comparable to that in the basal forebrain, were seen in the olfactory bulb and cerebellum, suggesting that NGF may be transported into these regions by unidentified neurons.     

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.     

昆虫嗅觉机制的研究进展

嗅觉机制对于昆虫选择栖息地、获得食物、趋利避害、传递讯息、群集以及繁殖等许多行为起到重要作用。因此,通过研究昆虫嗅觉系统,可以阐释嗅觉发生过程中的普遍机理,还有助于理解昆虫嗅觉活动与其整个生命活动之间的联系,进而为高等动物特别是人的嗅觉研究提供科学依据。并且通过对昆虫嗅觉机理的研究,发展出了一系列新的害虫治理方法,为害虫防治提供了新的思路。近年来,随着生物化学、分子生物学、昆虫行为学和昆虫电生理学的深入研究,科技人员发现了许多相关的嗅觉活性分子和嗅觉相关基因,从分子层面对昆虫嗅觉机制进行解释。本文综述了气味信号通过嗅感器转变为电信号,并由昆虫触角叶编码整合,最终传递到前脑整个过程中所涉及的分子组件及昆虫体内生理生化等方面有关进展。     

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.     

Role of olfactory sense in pregnancy block by strange males

Pregnancy is blocked in a high proportion of recently mated female mice exposed to strange males. This reaction is virtually abolished by the prior removal of the olfactory bulbs of the female. The smell of the strange male appears to be the primary stimulus in the exteroceptive block to pregnancy in mice.     

Carnosine in the primary olfactory pathway

Carnosine (beta-alanyl-L-histidine) is present in mouse olfactory bulbs and nasal olfactory epithelium at concentrations exceeding that previously reported for any brain region of any species. After peripheral deafferentation, carnosine concentrations in the olfactory bulbs decrease to less than 10 percent that of normal, while other amino compounds are unaffected. Carnosine appears to be highly localized to the primary olfactory pathway.     

An interneuronal chemoreceptor required for olfactory imprinting in C. elegans

Animals alter their behavioral patterns in an experience-dependent manner. Olfactory imprinting is a process in which the exposure of animals to olfactory cues during specific and restricted time windows leaves a permanent memory ("olfactory imprint") that shapes the animal's behavior upon encountering the olfactory cues at later times. We found that Caenorhabditis elegans displays olfactory imprinting behavior that is mediated by a single pair of interneurons. To function in olfactory imprinting, this interneuron pair must express a G protein-coupled chemoreceptor family member encoded by the sra-11 gene. Our study provides insights into the cellular and molecular basis of olfactory imprinting and reveals a function for a chemosensory receptor family member in interneurons.     

空间嗅觉设计研究进展及在图书馆应用的思考

[目的 /意义]嗅觉能唤起人的情感和认知,空间嗅觉设计作为空间设计的重要部分,影响着用户的行为绩效。通过对国内外空间嗅觉设计相关文献的分析和解读,归纳空间嗅觉设计的效用,总结嗅觉体验的设计影响机理,为空间嗅觉设计在图书馆类公共文化服务机构的应用提供理论依据。[方法 /过程]采用文献调研和内容分析法,对空间嗅觉引起的情绪、记忆和行为变化进行重点解析,梳理国内外对空间嗅觉作用的研究,总结国内外空间嗅觉设计的研究进展和应用趋势。[结果 /结论]国外对空间嗅觉设计已经在的研究场景集中在学习情景、商业购物情景等特殊情境下的嗅觉体验。相比之下,国内的空间嗅觉设计研究尚停留在理论探讨阶段,实证研究尚待探索。未来图书馆要基于用户嗅觉体验视角创设未来学习中心需要更加关注气味与图书馆的一致性、气味对图书馆用户在馆行为的影响。     

DNA topoisomerase IIbeta and neural development

DNA topoisomerase IIbeta is shown to have an unsuspected and critical role in neural development. Neurogenesis was normal in IIbeta mutant mice, but motor axons failed to contact skeletal muscles, and sensory axons failed to enter the spinal cord. Despite an absence of innervation, clusters of acetylcholine receptors were concentrated in the central region of skeletal muscles, thereby revealing patterning mechanisms that are autonomous to skeletal muscle. The defects in motor axon growth in IIbeta mutant mice resulted in a breathing impairment and death of the pups shortly after birth.     

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。     

Chemical Scent Constituents in the Urine of the Red Fox (Vulpes vulpes L.) During the Winter Season

Four volatile chemical compounds have been identified as apparently unique constituents in urines of red foxes (both sexes) during the winter season when mating occurs. Quinaldine was found only in male fox urine. Several other compounds identified are found in other species also. Some or all of these compounds may function in olfactory communication in the red fox.     

Odor stimuli trigger influx of calcium into olfactory neurons of the channel catfish

Olfactory transduction is thought to be mediated by a G protein-coupled increase in intracellular adenosine 3',5'-monophosphate (cAMP) that triggers the opening of cAMP-gated cation channels and results in depolarization of the plasma membrane of olfactory neurons. In olfactory neurons isolated from the channel catfish, Ictalurus punctatus, stimulation with olfactory stimuli (amino acids) elicits an influx of calcium that leads to a rapid increase in intracellular calcium. In addition, in a reconstitution assay a plasma membrane calcium channel has been identified that is gated by inositol-1,4,5-trisphosphate (IP3), which could mediate this calcium influx. Together with previous studies indicating that stimulation with olfactory stimuli leads to stimulation of phosphoinositide turnover in olfactory cilia, these data suggest that an influx of calcium triggered by odor stimulation of phosphoinositide turnover may be an alternate or additional mechanism of olfactory transduction.     

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。     

Detection of near-atmospheric concentrations of CO2 by an olfactory subsystem in the mouse

Carbon dioxide (CO2) is an important environmental cue for many organisms but is odorless to humans. It remains unclear whether the mammalian olfactory system can detect CO2 at concentrations around the average atmospheric level (0.038%). We demonstrated the expression of carbonic anhydrase type II (CAII), an enzyme that catabolizes CO2, in a subset of mouse olfactory neurons that express guanylyl cyclase D (GC-D+ neurons) and project axons to necklace glomeruli in the olfactory bulb. Exposure to CO2 activated these GC-D+ neurons, and exposure of a mouse to CO2 activated bulbar neurons associated with necklace glomeruli. Behavioral tests revealed CO2 detection thresholds of approximately 0.066%, and this sensitive CO2 detection required CAII activity. We conclude that mice detect CO2 at near-atmospheric concentrations through the olfactory subsystem of GC-D+ neurons.     

"Pure" human hematopoietic progenitors: permissive action of basic fibroblast growth factor

Methodology has been developed that enables virtually complete purification and abundant recovery of early hematopoietic progenitors from normal human adult peripheral blood. A fraction of the pure progenitors is multipotent (generates mixed colonies) and exhibits self-renewal capacity (gives rise to blast cell colonies). This methodology provides a fundamental tool for basic and clinical studies on hematopoiesis. Optimal in vitro cloning of virtually pure progenitors requires not only the stimulatory effect of interleukin-3, granulocyte-macrophage colony-stimulating factor, and erythropoietin, but also the permissive action of basic fibroblast growth factor. These findings suggest a regulatory role for this growth factor in early hematopoiesis.     

Synthesis of compounds with properties of leukotrienes C4 and D4 in gerbil brains after ischemia and reperfusion

6-Sulfidopeptide-containing leukotriene-like immunoreactivity was synthesized in gerbil forebrains after bilateral common carotid occlusion and reperfusion. At 5, 10, or 15 minutes of ischemia, concentrations increased significantly and became more marked on reperfusion. Immunoreactivity was highest in forebrain gray matter and was below the detection limit of the assay in brain regions remote from the zone of ischemia. In vitro experiments with vascular cells and organ cultures of cerebral arteries indicate that the cerebral blood vessel wall is not a major source of biosynthetic activity in the brain. These experiments demonstrate leukotriene biosynthesis by the brain. Because synthesis occurs during ischemia and reperfusion and because leukotrienes are potent vasoconstrictors and promoters of tissue edema, they may play a role in the pathophysiology of cerebral ischemia.