僧帽細胞

WordNet

small room in which a monk or nun lives (同)cubicle
a device that delivers an electric current as the result of a chemical reaction (同)electric cell
a room where a prisoner is kept (同)jail cell, prison cell
(biology) the basic structural and functional unit of all organisms; they may exist as independent units of life (as in monads) or may form colonies or tissues as in higher plants and animals
any small compartment; "the cells of a honeycomb"
a small unit serving as part of or as the nucleus of a larger political movement (同)cadre
relating to or resembling the miter worn by some clerics
of or relating to or located in or near the mitral valve; "mitral insufficiency"

PrepTutorEJDIC

(刑務所の)『独房』;(修道院の)小さい独居室 / (ミツバチの)みつ房,巣穴 / 小さい部屋 / 『細胞』 / 電池 / 花粉室 / (共産党などの)細胞

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/03/07 02:05:31」(JST)

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Mitral cells are neurons that are part of the olfactory system. They are located in the olfactory bulb in the mammalian central nervous system. They receive information from the axons of olfactory receptor neurons, forming synapses in neuropils called glomeruli. Axons of the mitral cells transfer information to a number of areas in the brain, including the piriform cortex, entorhinal cortex, and amygdala. Mitral cells receive excitatory input from olfactory sensory neurons and external tufted cells on their primary dendrites, whereas inhibitory input arises either from granule cells onto their lateral dendrites and soma or from periglomerular cells onto their dendritic tuft. Mitral cells together with tufted cells form an obligatory relay for all olfactory information entering from the olfactory nerve. Mitral cell output is not a passive reflection of their input from the olfactory nerve. In mice, each mitral cell sends a single primary dendrite into a glomerulus receiving input from a population of olfactory sensory neurons expressing identical olfactory receptor proteins, yet the odor responsiveness of the 20-40 mitral cells connected to a single glomerulus (called sister mitral cells^[1]) is not identical to the tuning curve of the input cells, and also differs between sister mitral cells.^[2] The exact type of processing that mitral cells perform with their inputs still a matter of controversy. One prominent hypothesis is the notion that mitral cells transform the strength of olfactory input into a timing code, where odor concentration is encoded in the phase of mitral cell firing relative to the sniff cycle. A second (not necessarily exclusive) hypothesis is the idea of decorrelation in the olfactory bulb network, where the olfactory bulb network acts as a dynamical system whose action over time increases some (abstract) measure of distance between representations of highly similar odorants. Support for the second hypothesis comes primarily from research in zebrafish (where mitral and tufted cells cannot be distinguished).^[3]

Morphology

Mitral cells are a neuronal cell type in the mammalian olfactory bulb, distinguished by the position of their somata located in an orderly row in the mitral cell layer of the bulb.^[4] They typically have a single primary dendrite, which they project into a single glomerulus in the glomerular layer, and a few lateral dendrites that project laterally in the external plexiform layer. Mitral cells are closely related to the second type of projection neuron in the mammalian bulb, known as the tufted cell. In lower vertebrates, mitral and tufted cells cannot be morphologically distinguished from tufted cells, and their morphology is substantially different from the mammalian mitral cells. The cell often have multiple primary dendrites innervating different glomeruli and they are sometimes called simply projection neurons, to indicate that they are the main neural element which project outside the olfactory bulb. The morphology of mitral cells was an advantage in early studies of synaptic processing, because the soma and the primary dendrite could be independently stimulated by appropriate positioning of stimulating electrodes in different layers of the olfactory bulb.^[5]

Synaptic processing

Mitral cells are a key part of the olfactory bulb microcircuit. Mitral cells receive input from at least four cell types: olfactory sensory neurons, periglomerular neurons, external tufted cells and granule cells. The synapses made by external tufted cells and olfactory sensory neurons are excitatory, whereas those of granule cells and periglomerular neurons are inhibitory. In addition, sister mitral cells are reciprocally connected by gap junctions. The mitral to granule and mitral to periglomerular cell synapse was the first description of the rather atypical reciprocal dendrodenritic synapses (in contrast to the more common axodendritic synapse). The action of the full glomerular microcircuit is a topic that is under intense scientific investigation. Certain principles are starting to emerge. One discovery points to the idea of the microcircuit between mitral, tufted and periglomerular cells in separating the output of mitral and tufted cells in time.^[6] It appears that tufted cells receive strong olfactory nerve input,^[7] fire close to inhalation onset and their firing phase is relatively concentration insensitive, whereas mitral cells receive relatively weak olfactory nerve input^[8] and strong periglomerular inhibition, which delays their firing relative to the tufted cells. This escape from inhibition can be sped up by increasing the stimulating odorant concentration, and thus mitral cell firing phase acts as one possible way the olfactory system encodes concentration. The role of the mitral cell lateral dendrite and granule cell circuit is currently a bit more uncertain. One possible hypothesis implicates the system in forming sparse representation which enable more effective pattern separation.^[9] The action of this circuit is heavily influenced by both short term and long term plasticity and ongoing granule cell neurogenesis.^[10] The circuit requires the animal to be awake if it is to have full functionality.

Projection targets

Mitral and tufted cells project to various targets in the brain. Most importantly, projections target the olfactory cortex, where odor information can be integrated with input from other sensory modalities and used to drive behavior. Tufted cells project mainly to the anterior olfactory nucleus, a center that also performs comparison between left and right side olfactory input. Mitral cells project to the olfactory tubercle, where chemical information is integrated with auditory signals. Mitral cells carrying pheromonal inputs project to the amygdala and hypothalamus to drive instinctive behaviors. A major integrative center is the piriform cortex, where mitral cells make non-topographic projections to pyramidal cells which integrate information across glomeruli. Projections also go to the entorhinal cortex. Anatomical connectivity of a mitral cell axon can be quite different depending on the target structure. Whereas piriform cortex is innervated mostly randomly, projections to the anterior olfactory nucleus and amygdala retain some topographic order. Finally, mitral cell axons also make intrabulbar connections to granule cells and in the mouse olfactory system they project selectively to granule cells underlying the second ipsilateral homotypic (expressing the same olfactory receptor) glomerulus.

References

^ Dhawale et.al (2010) Non-redundant odor coding by sister mitral cells revealed by light addressable glomeruli in the mouse. Nature Neuroscience
^ Kikuta et.al (2013) Odorant response properties of individual neurons in an olfactory glomerular module. Neuron
^ R.W.Friedrich, G.Laurent (2001) Dynamic optimization of odor representations by slow temporal patterning of mitral cell activity. Science Vol 291
^ Graziadei, Dryer (1994) Mitral cell dendrites: a comparative approach. Anatomy and Embryology
^ G.M.Shepherd editor (2004) Synaptic organization of the brain. 4th edition
^ Fukunaga et.al (2013) Two distinct channels of olfactory bulb output. Neuron
^ De Saint Jan et.al (2009) External tufted cells drive the output of olfactory bulb glomeruli. Journal of Neuroscience
^ Gire et.al (2012) Mitral cells in the olfactory bulb are mainly excited through a multistep signaling path. Journal of Neuroscience
^ Rinberg, Koulakov (2011) Sparse incomplete representations: A potential role for olfactory granule cells. Neuron
^ Kato et.al (2012) Dynamic Sensory Representations in the Olfactory Bulb: Modulation by Wakefulness and Experience. Neuron

External links

NIF Search - Mitral Cell via the Neuroscience Information Framework

UpToDate Contents

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1. 僧帽弁輪石灰化 mitral annular calcification
2. 虚血性僧帽弁閉鎖不全症 ischemic mitral regurgitation
3. 僧帽弁狭窄症に対する経皮的バルーン僧帽弁切開術 percutaneous mitral balloon valvotomy for mitral stenosis
4. 経カテーテル僧帽弁修復 transcatheter mitral valve repair
5. 僧帽弁狭窄症の外科的マネージメント surgical management of mitral stenosis

English Journal

Main and accessory olfactory bulbs and their projections in the brain anticipate feeding in food-entrained rats.

Caba M1, Pabello M, Moreno ML, Meza E.
Chronobiology international.Chronobiol Int.2014 Oct;31(8):869-77. doi: 10.3109/07420528.2014.918625. Epub 2014 Jun 10.
The olfactory bulb (OB) has a circadian clock independent of the suprachiasmatic nucleus, but very little is known about the functional significance of its oscillations. The OB plays a major role in food intake as it contributes to the evaluation of the hedonic properties of food, it is necessary fo
PMID 24915133

Brain-state dependent uncoupling of BOLD and local field potentials in laminar olfactory bulb.

Gong L1, Li B1, Wu R1, Li A2, Xu F3.
Neuroscience letters.Neurosci Lett.2014 Sep 19;580:1-6. doi: 10.1016/j.neulet.2014.07.034. Epub 2014 Jul 29.
The neural activities of the olfactory bulb (OB) can be modulated significantly by internal brain states. While blood oxygenation level dependent functional MRI (BOLD-fMRI) has been extensively applied to study OB in small animals, the relationship between BOLD signals and electrophysiological signa
PMID 25079901

Altered synaptic transmission at olfactory and vomeronasal nerve terminals in mice lacking N-type calcium channel Cav2.2.

Weiss J1, Pyrski M, Weissgerber P, Zufall F.
The European journal of neuroscience.Eur J Neurosci.2014 Sep 5. doi: 10.1111/ejn.12713. [Epub ahead of print]
We investigated the role of voltage-activated calcium (Cav) channels for synaptic transmission at mouse olfactory and vomeronasal nerve terminals at the first synapse of the main and accessory olfactory pathways, respectively. We provided evidence for a central role of the N-type Cav channel subunit
PMID 25195871

Japanese Journal

右心不全によるショックにて緊急手術を施行した巨大右心房原発悪性リンパ腫の1例

坂本滋,坂本大輔
日本心臓血管外科学会雑誌 43(1), 27-31, 2014
僧帽弁置換術，三尖弁輪形成術，C型肝炎と肝硬変の既往歴を有した巨大右心房原発悪性リンパ腫により，臨床症状出現から数日後に右心不全・ショック状態に陥った70歳女性の症例を経験した．緊急で人工心肺下に腫瘍を摘出し，EPTFEパッチによる右心房自由壁再建と腫瘍が三尖弁輪下部に浸潤していたため再三尖弁形成術はあきらめ，生体弁による三尖弁置換術を施行した．切除病理組織検査より瀰漫性大細胞型B細胞性悪性リンパ …
NAID 130004548488

The engraftment and differentiation of transplanted bone marrow-derived cells in the olfactory bulb after methimazole administration

Noda Yohei,Nishizaki Kazunori,Yoshinobu Junko,Orita Yorihisa,Tsujigiwa Hidetsugu,Yamada Masao
Acta Oto-laryngologica 133(9), 951-956, 2013-09
… Conclusion: Bone marrow-derived cells can be engrafted in the olfactory bulb and a few cells can differentiate into mitral/tufted cells in the olfactory bulb. … Immunostaining was performed to confirm the cell types of bone marrow-derived cells expressing GFP. … Double immunostaining for GFP and Iba1 or TBX21 showed that a large population of the GFP-positive cells had characteristics of microglia/macrophages and a few cells had characteristics of mitral/tufted cells. …
NAID 120005359096

Effects of Inhaled Tiotropium on Left Ventricular Diastolic Function in Chronic Obstructive Pulmonary Disease Patients after Pulmonary Resection

NOJIRI Takashi,YAMAMOTO Kazuhiro,MAEDA Hajime,TAKEUCHI Yukiyasu,FUNAKOSHI Yasunobu,MAEKURA Ryoji,OKUMURA Meinoshin
Annals of thoracic and cardiovascular surgery 18(3), 206-211, 2012-06-01
… B-type natriuretic peptide, white blood cell counts, and C-reactive protein levels before and after inhaled tiotropium treatment were also examined.Results: There were no significant differences between before and after treatment in forced vital capacity and left ventricular ejection fraction. …
NAID 10030789515