Restricted diffusion and extracellular space in the insect retina

1977 ◽  
Vol 113 (3) ◽  
pp. 257-282 ◽  
Author(s):  
S. R. Shaw
Keyword(s):  
Extracellular Space ◽  
Restricted Diffusion ◽  
Insect Retina

Scanning electron microscopic study of collagen fibrillogenesis and extracellular compartmentalization in the chick embryo tendon

1986 ◽  
Vol 44 ◽  
pp. 208-209
Author(s):  
Grace C.H. Yang
Keyword(s):  
Chick Embryo ◽  
Extracellular Space ◽  
Fibroblast Cell ◽  
Collagen Fibrils ◽  
Electron Microscopic ◽  
Voltage Electron ◽  
Scanning Electron Microscopic Study ◽  
Microscopic Studies ◽  
And Function

The size and organization of collagen fibrils in the extracellular matrix is an important determinant of tissue structure and function. The synthesis and deposition of collagen involves multiple steps which begin within the cell and continue in the extracellular space. High-voltage electron microscopic studies of the chick embryo cornea and tendon suggested that the extracellular space is compartmentalized by the fibroblasts for the regulation of collagen fibril, bundle, and tissue specific macroaggregate formation. The purpose of this study is to gather direct evidence regarding the association of the fibroblast cell surface with newly formed collagen fibrils, and to define the role of the fibroblast in the control and the precise positioning of collagen fibrils, bundles, and macroaggregates during chick tendon development.

Comparison of changes evoked by GABA (γ-aminobutyric acid) and anoxia in [K+]o, [Cl-]o, and [Na+]o in stratum pyramidale and stratum radiatum of the guinea pig hippocampus

2000 ◽  
Vol 78 (5) ◽  
pp. 378-391 ◽  
Author(s):  
G V Obrocea ◽  
M E Morris
Keyword(s):  
Guinea Pig ◽  
Extracellular Space ◽  
Hippocampal Slices ◽  
Brain Slices ◽  
Receptor Activation ◽  
Ion Concentration ◽  
Aminobutyric Acid ◽  
Stratum Radiatum ◽  
Bicuculline Methiodide ◽  
Stratum Pyramidale

Ion-selective microelectrode recordings were made to assess a possible contribution of extracellular γ-aminobutyric acid (GABA) accumulation to early responses evoked in the brain by anoxia and ischemia. Changes evoked by GABA or N2 in [K+]o, [Cl-]o, [Na+]o, and [TMA+]o were recorded in the cell body and dendritic regions of the stratum pyramidale (SP) and stratum radiatum (SR), respectively, of pyramidal neurons in CA1 of guinea pig hippocampal slices. Bath application of GABA (1-10 mM) for approximately 5 min evoked changes in [K+]o and [Cl-]o with respective EC50 levels of 3.8 and 4.1 mM in SP, and 4.7 and 5.6 mM in SR. In SP 5 mM GABA reversibly increased [K+]o and [Cl-]o and decreased [Na+]o; replacement of 95% O2 -5% CO2 by 95% N2 -5% CO2 for a similar period of time evoked changes which were for each ion in the same direction as those with GABA. In SR both GABA and N2 caused increases in [K+]o and decreases in [Cl-]o and [Na+]o. The reduction of extracellular space, estimated from levels of [TMA+]o during exposures to GABA and N2, was 5-6% and insufficient to cause the observed changes in ion concentration. Ion changes induced by GABA and N2 were reversibly attenuated by the GABAA receptor antagonist bicuculline methiodide (BMI, 100 µM). GABA-evoked changes in [K+]o in SP and SR and [Cl-]o in SP were depressed by >=90%, and of [Cl-]o in SR by 50%; N2-evoked changes in [K+]o in SP and SR were decreased by 70% and those of [Cl-]o by 50%. BMI blocked Δ [Na+]o with both GABA and N2 by 20-30%. It is concluded that during early anoxia: (i) accumulation of GABA and activation of GABAA receptors may contribute to the ion changes and play a significant role, and (ii) responses in the dendritic (SR) regions are greater than and (or) differ from those in the somal (SP) layers. A large component of the [K+]o increase may involve a GABA-evoked Ca2+-activated gk, secondary to [Ca2+]i increase. A major part of [Cl-]o changes may arise from GABA-induced gCl and glial efflux, with strong stimulation of active outward transport and anion exchange at SP, and inward Na+/K+/2Cl- co-transport at SR. Na+ influx is attributable mainly to Na+-dependent transmitter uptake, with only a small amount related to GABAA receptor activation. Although the release and (or) accumulation of GABA during anoxia might be viewed as potentially protectant, the ultimate role may more likely be an important contribution to toxicity and delayed neuronal death. Key words: brain slices, ion-selective microelectrodes, stratum pyramidale, stratum radiatum, bicuculline methiodide, extracellular space shrinkage.

Aldolase C/Zebrin II is Released to the Extracellular Space after Stroke and Inhibits the Network Activity of Cortical Neurons

2006 ◽  
Vol 31 (11) ◽  
pp. 1297-1303 ◽  
Author(s):  
Stephanie Linke ◽  
Philipp Goertz ◽  
Stephan L. Baader ◽  
Volkmar Gieselmann ◽  
Mario Siebler ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Extracellular Space ◽  
Network Activity ◽  
Aldolase C ◽  
Zebrin Ii

Restricted diffusion of polarised gas in aerogels

2003 ◽  
Vol 329-333 ◽  
pp. 303-304 ◽  
Author(s):  
Geneviève Tastevin ◽  
Pierre-Jean Nacher ◽  
Jamal Choukeife
Keyword(s):  
Restricted Diffusion

MRI Demonstrates Restricted Diffusion in Distal Optic Nerve in Atypical Optic Neuritis

2010 ◽  
Vol 30 (1) ◽  
pp. 31-33 ◽  
Author(s):  
Oriel Spierer ◽  
Liat Ben Sira ◽  
Igal Leibovitch ◽  
Anat Kesler
Keyword(s):  
Optic Nerve ◽  
Optic Neuritis ◽  
Restricted Diffusion
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