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Extracellular - Wikipedia, the free encyclopedia In cell biology, molecular biology and related fields, the word extracellular (or sometimes extracellular space) means "outside the cell". This space is usually taken to be outside the plasma membranes, and occupied by fluid. The term 'extracellular' is often used in reference to the extracellular fluid (ECF) which composes about 15 litres of the average human body. en.wikipedia.org /wiki/Extracellular   (213 words)

The Extracellular Matrix of Animals We focus on the extracellular matrix of vertebrates, but the origins of the extracellular matrix are very ancient and virtually all multicellular organisms, make it; examples include the cuticles of worms and insects, the shells of mollusks, and, as we discuss later, the cell walls of plants. It is also important as a space filler during embryonic development, where it can be used to force a change in the shape of a structure, as a small quantity expands with water to occupy a large volume (see Figure 19-37). After the fibrils have formed in the extracellular space, they are greatly strengthened by the formation of covalent cross-links between lysine residues of the constituent collagen molecules (Figure 19-46). www.ncbi.nlm.nih.gov /books/bv.fcgi?rid=mboc4.section.3532   (8975 words)

Modulation of AV nodal and Hisian conduction by changes in extracellular space -- Lurie et al. 276 (3): 953 -- AJP - ... Measurements of extracellular space were performed in both the preparation hearts as well as in hearts from the donor dogs. Measurement of extracellular space in donor hearts, control preparations, and preparations after infusion of mannitol demonstrated that the ratio of AV node to contractile muscle was ~2.2:1.0 under control conditions. Measurement of extracellular space in the rabbit AV node. ajpheart.physiology.org /cgi/content/full/276/3/H953   (3942 words)

The Extracellular Matrix of Animals 17 Until recently the vertebrate extracellular matrix was thought to serve mainly as a relatively inert scaffolding to stabilize the physical structure of tissues. The extracellular domain of this transmembrane proteoglycan carries a variable number of chondroitin sulfate and heparan sulfate GAG chains, while its intracellular domain is thought to interact with the actin cytoskeleton in the cell cortex. After the fibrils form in the extracellular space, they are greatly strengthened by the formation of covalent cross-links between lysine residues of the constituent collagen molecules (Figure 19-45). www.ncbi.nlm.nih.gov /books/bv.fcgi?call=bv.View..ShowSection&rid=cell.section.5140   (8302 words)

Distribution of TmDOTP5- in rat tissues: TmDOTP5- vs. CoEDTA- as markers of extracellular tissue space -- Makos et al. ... Traditionally, the volume of the ECS is measured by using a chemical marker that is known to be confined to that space. Extracellular space, water, and ion concentration in the hypertrophied rat myocardium. Determination of the extracellular space with nonradioactive Co EDTA and simultaneous estimation of Na, K, Ca, and Mg contents in isolated guinea-pig heart preparations by atomic absorption spectrometry. jap.physiology.org /cgi/content/full/85/5/1800   (3528 words)

Bidomain theory Cardiac tissue consists of cells which are tightly coupled by intercellular junctions which connect the intracellular space of one cell to the intracellular space of the surrounding cells. The intracellular space is connected to the interstitial space by a membrane patch consisting of resistive and capacitive components. Physically, the extracellular space of a cardiac cell on the boundary of a tissue in a surrounding bath is in contact with the monodomain bath region. home.wlu.edu /~easonj/bidomain.html   (1148 words)

Tissue spaces in rat heart, liver, and skeletal muscle in vivo -- Cieslar et al. 275 (5): 1530 -- AJP - Regulatory, ... By subtracting the interstitial space from the inulin Extracellular volume decreases while cell volume is maintained by ion uptake in rat brain during acute hypernaturemia. Determination of extracellular space and intracellular electrolytes in rat liver in vivo. ajpregu.physiology.org /cgi/content/full/275/5/R1530   (4113 words)

Microelectrode and Nanoelectrode Arrays Used in Cell Monitoring - Current Research Activity Extracellular signals are smaller than transmembrane potentials, depending on the distance of the signal source to the electrode. Due to the low-pass filtering properties of the extracellular space, extracellular signal amplitudes decrease with increasing distance of the signal source to the electrode. The transmembrane current and the extracellular potential follow the same time course, and are roughly equal to the first derivative of the transmembrane potential. www.azonano.com /details.asp?ArticleID=1212   (1411 words)

Nanostructure of the epidermal extracellular space as observed by cryo-electron microscopy of vitreous sections of ...   (Site not responding. Last check: 2007-10-20) Nanostructure of the epidermal extracellular space as observed by cryo-electron microscopy of vitreous sections of human skin. The extracellular space of viable epidermis contains desmosomes, expressing a characteristic extracellular transverse approximately 5 nm periodicity, interconnected by a relatively electron lucent inter-desmosomal space. The extracellular space of cornified epidermis contains approximately 9, approximately 14, approximately 25, approximately 33, approximately 39, approximately 44, and approximately 48 nm thick regions in turn containing one, two, four, six, eight, eight, and ten parallel electron-dense lines, respectively, between adjacent corneocyte lipid envelopes. www.3dem-noe.org.cob-web.org:8888 /publications/publ_014.html   (212 words)

Inosine Although inosine is constitutively present at low levels in the extracellular space, metabolically stressful conditions, such as those that occur during injury, ischemia, and inflammation dramatically increase its extracellular concentrations. Once inosine reaches high concentrations inside the cell, it is shunted into the extracellular space via the operation of bidirectional equilibrative nucleoside transporters. Extracellular inosine and adenosine gain access to the intracellular space through both equilibrative and concentrative nucleoside transporters and adenosine and inosine can compete for these transporters. www.inotekcorp.com /content/inosine.asp   (320 words)

RN S 4 Fluid elec Balance Urine output decreases because fluid shifts out of the intravascular space; the kidneys then receive less blood flow and attempt to compensate by decreasing urine output. Extracellular volume is the most protected aspect of body fluid balance because without an adequate extracellular volume, blood pressure cannot be maintained. The renin-angiotensin-aldosterone hormone system then regulates extracellular volume by adjusting fluid intake and the urinary excretion of sodium, chloride, and water to maintain the extracellular volume within normal limits. www.krcintranet.com /s122.htm   (1016 words)

Electrical Resistances of Interstitial and Microvascular Space as Determinants of the Extracellular Electrical Field ... Note that the extracellular electrode at the base of the muscle remains in place, whereas the position of the apical electrode is changed. this corresponds to a 120% increase of the interstitial space and the interstitial space on the extracellular resistance. circ.ahajournals.org /cgi/content/full/92/3/587   (4435 words)

Transient Hypoxia-Ischemia in Rats: Changes in Diffusion-Sensitive MR Imaging Findings, Extracellular Space, and Na ... In both age groups, the dynamic changes in extracellular space, which are presented as percentages of the prehypoxia baseline values, correspond well to the changes observed on DW MR images, which are presented as ipsilateral versus contralateral signal intensity ratios (I/C). with a shrinkage and reexpansion of the extracellular space. Distribution of the extracellular space during postnatal maturation of rat cerebral cortex. radiology.rsnajnls.org /cgi/content/full/223/1/65   (6421 words)

EXTRACELLULAR MATRIX (ECM) The extracellular matrix (ECM) is a complex structural entity surrounding and supporting cells that are found within mammalian tissues. Following completion of processing the procollagens are secreted into the extracellular space where extracellular enzymes remove the pro-domains. Accompanying fibril formation is the oxidation of certain lysine residues by the extracellular enzyme lysyl oxidase foming reactive aldehydes. web.indstate.edu /thcme/mwking/extracellularmatrix.html   (820 words)

Extracellular Calcium   (Site not responding. Last check: 2007-10-20) One fifth of the mammalian brain is comprised of extracellular space (ECS). The extracellular space is not empty, but instead comprises a complex network of proteins and a variety of molecular species. One extracellular species, calcium, holds a prominent position as one of the most important messengers known in the brain. nba.uth.tmc.edu /homepage/eagleman/calcium.html   (981 words)

Explorations in Medicine and the Biosciences From the extracellular spaces, the drug can pass through the cell wall or cell membrane into the intracellular space. We are fundamentally interested in measuring the concentration (in mg/mL) in the plasma, the intracellular space, and the extracellular space. The therapeutic level is 0.05 mg/mL (concentration in the plasma, extracellular space, and intracellular space). www.shodor.org /succeed/biomed/labs/flucyt.html   (962 words)

[No title] Hence, neighboring neurons in an assembly are expected to fire in a shifting pattern and to contribute to a complex sequence of superimposing waves of Ca reduction in their extracellular space. The phases of excitation and stationarity are in the former case mediated by diffusion, in the latter by passive electrononic current flow. As carrier of diffusible substances, the extended medium of extracellular space functions as modulator of the excitability cycle of ion channels in the neuronal membrane. www.ece.utexas.edu /~werner/Excitable_Media/excitable_media.html   (4241 words)

Evidence for Chelatable Zinc in the Extracellular Space of the Hippocampus, But Little Evidence for Synaptic Release of ... not arises from the release of Zn to the extracellular space molecules in the extracellular space and is chelated by FluoZin-3. Cragg B (1980) Preservation of extracellular space during fixation of the brain for electron microscopy. www.jneurosci.org /cgi/content/full/23/17/6847   (6439 words)

Transmembrane receptor - Wikipedia, the free encyclopedia The extracellular domain is the part of the receptor that sticks out of the membrane on the outside of the cell or organelle. By definition, a receptor's main function is to recognize and respond to a specific ligand, for example, a neurotransmitter or hormone (although certain receptors respond also to changes in transmembrane potential), and in many receptors these ligands bind to the extracellular domain. Upon activation of an extracellular domain by binding of the appropriate ligand, the pore becomes accessible to ions, which then pass through. en.wikipedia.org /wiki/Transmembrane_receptor   (537 words)

Modeling Extracellular Field Potentials and the Frequency-Filtering Properties of Extracellular Space -- Bédard ... the conductivity of the extracellular space is constant on average, Because the extracellular space is composed of alternating fluids The extracellular potential was calculated from a conductance-based spiking neuron model (identical to that of Fig. www.biophysj.org /cgi/content/full/86/3/1829   (4836 words)

Resistance of Retinal Extracellular Space to Ca2+ Level Decrease: Implications for the Synaptic Effects of Divalent ... Resistance of Retinal Extracellular Space to Ca2+ Level Decrease: Implications for the Synaptic Effects of Divalent Cations -- Dmitriev et al. Resistance of Retinal Extracellular Space to Ca Level Decrease: Implications for the Synaptic Effects of Divalent Cations. the concentration of divalent cations in the extracellular space jn.physiology.org /cgi/content/full/82/1/283   (5212 words)

Oviduct Cells Express the Cyclic AMP-Adenosine Pathway -- Cometti et al. 69 (3): 868 -- Biology of Reproduction Extracellular concentrations of adenosine (A) and cAMP (B) in oviduct cells stimulated with or without adenylyl cyclase stimulators, forskolin (FOR; 10 µM) plus isoproterenol (ISO; 0.1 µM) in the presence and absence of adenosine catabolism inhibitors (ACI) EHNA (10 µM). The extracellular ATP pathway entails the metabolism of adenine to the extracellular space [32], inhibition by DPSPX of the www.biolreprod.org /cgi/content/full/69/3/868   (5325 words)

Diffusion of Epidermal Growth Factor in Rat Brain Extracellular Space Measured by Integrative Optical Imaging -- Thorne ... Molecules migrate through the extracellular space (ECS) along a tortuous path that is governed by their size. Lehmenkühler A, Syková E, Svoboda J, Zilles K, and Nicholson C. Extracellular space parameters in the rat neocortex and subcortical white matter during postnatal development determined by diffusion analysis. Geometric and viscous components of the tortuosity of the extracellular space in the brain. jn.physiology.org /cgi/content/full/92/6/3471   (5956 words)

Mechanisms for maintaining extracellular glutamate levels in the anoxic turtle striatum -- Milton et al. 282 (5): 1317 ... extracellular space is thought to occur by this reversal of glutamate Effects of anoxia on extracellular levels of inhibitory and excitatory amino acids measured by intracerebral microdialysis in the striatum of freshwater turtles exposed to 4-h anoxia at 25°C. Time 0 indicates the start of ventilation on 99.99% nitrogen. Massieu, L, Morales-Villagran A, and Tapia R. Accumulation of extracellular glutamate by inhibition of its uptake is not sufficient for inducing neuronal damage: an in vivo microdialysis study. ajpregu.physiology.org /cgi/content/full/282/5/R1317   (4250 words)

P2Y Receptor-Mediated Stimulation of Muller Glial DNA Synthesis -- Moll et al. 43 (3): 766 -- Investigative ... Extracellular ATP was tested at concentrations of 0.1, 1, 10, 50, 100, 250, and 500 µM. The curve was fitted with f = (b · x)/(x + a), with a = 5.9 µM and b = 0.435. The mitogenic effect of ATP was dependent on an influx of calcium from the extracellular space. After a changing was made to a calcium-containing extracellular solution, there was a prolonged steady state increase in intracellular free calcium (mean ± SD curve of 40 cells). www.iovs.org /cgi/content/full/43/3/766   (4819 words)

CLV3 Is Localized to the Extracellular Space, Where It Activates the Arabidopsis CLAVATA Stem Cell Signaling Pathway -- ... CLV3 Is Localized to the Extracellular Space, Where It Activates the Arabidopsis CLAVATA Stem Cell Signaling Pathway -- Rojo et al. in the plasma membrane and/or the apoplastic space and that CLV3 is localized to the extracellular space and is predicted to travel through the apoplast from the L1 and L2 to the CLV1-expressing cells in the L3, which are isolated symplastically from the tunica (L1 and L2). www.plantcell.org /cgi/content/full/14/5/969   (5529 words)

Tracer kinetics analysis of the extracellular spaces in saline perfused hearts Low molecular weight markers (LMM), such as sulphate ion and sucrose, are widely used to define extracellular space size despite indications that they penetrate the cell. ANIMALS AND METHODS: The size of extracellular space in guinea pig hearts perfused with crystalloid solution (hydrated hearts) was determined morphometrically and by mathematical model analysis of washout kinetics of LMM (35SO4, 14C-sucrose) or 3H-inulin. Comparable data were obtained from model simulation of tracer washout: 67 mL/kg wm for vascular space and 439 to 462 mL/kg wm for interstitial space. www.pulsus.com /europe/06_04/alie_ed.htm   (302 words)

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