In Vivo CCK Release by Microdialysis

2012 ◽  
Keyword(s):  
Cck Release

Evidence for indirect dietary regulation of cholecystokinin release in rats

1993 ◽  
Vol 265 (1) ◽  
pp. G107-G112 ◽  
Author(s):  
A. I. Sharara ◽  
E. P. Bouras ◽  
M. A. Misukonis ◽  
R. A. Liddle
Keyword(s):  
Direct Interaction ◽  
Dependent Manner ◽  
Intact Proteins ◽  
Dietary Regulation ◽  
Mucosal Cells ◽  
Protein Digests ◽  
Proximal Intestine ◽  
Cck Release

Food ingestion stimulates cholecystokinin (CCK) release from the proximal intestine, but the mechanisms involved are not well understood. To investigate this effect in vivo in intact rats, plasma CCK was measured after orogastric feeding of proteins, protein hydrolysates, amino acids, glucose, and starch. Intact proteins were the only nutrients to stimulate CCK release. The possibility of direct interaction between different dietary constituents and intestinal CCK-secreting endocrine cells was then examined using a perfusion system containing isolated mucosal cells from the rat duodenojejunum. The functional validity of this system was established by demonstrating that monitor peptide and bombesin both stimulated CCK release in a dose-dependent manner. The stimulatory effect of bombesin required extracellular calcium and was not inhibited by addition of tetrodotoxin. Perifusion of proteins, protein digests, and carbohydrates did not stimulate CCK release. These results indicate that proteins stimulate CCK release postprandially via an indirect mechanism, most likely related to inhibition of intraluminal trypsin. Perifusion of dispersed mucosal cells constitutes a reproducible model to investigate hormonal and peptidergic regulation of CCK release in vitro.

scholarly journals Red kidney bean lectin is a potent cholecystokinin releasing stimulus in the rat inducing pancreatic growth

Gut ◽  
1997 ◽  
Vol 41 (3) ◽  
pp. 333-338 ◽  
Author(s):  
K-H Herzig ◽  
S Bardocz ◽  
G Grant ◽  
R Nustede ◽  
U R Fölsch ◽  
...  
Keyword(s):  
Small Intestine ◽  
Specific Binding ◽  
Male Rats ◽  
Growth Effect ◽  
Control Group ◽  
Maximal Effect ◽  
Pancreatic Growth ◽  
Cck Release

Background—Lectins are proteins capable of specific binding to carbohydrates without altering their covalent structure. As an essential part of plants they are ingested in our daily diet. By binding to glycosyl side chains of receptors lectins can mimic or inhibit the action of the ligand. Oral administration of phytohaemagglutinin (PHA) in rats dose dependently induces growth of the small intestine and the pancreas by an unknown mechanism.Aims—To investigate the mechanism of PHA induced intestinal and pancreatic growth.Methods—Thirty day old male rats were pairfed for 10 days with lactalbumin as a control diet or lactalbumin plus PHA or purified soybean trypsin inhibitor (STI) as a positive control (42 mg/rat/day) with or without 20 μg of the cholecystokinin A (CCK-A) antagonist MK 329. To investigate further the effect of PHA on CCK release intestinal mucosal cells were isolated from rats which were continuously perfused in a perfusion apparatus. CCK release into the medium was assayed.Results—PHA and STI significantly stimulated growth of the pancreas and the small intestine. MK 329 blocked this growth effect in the pancreas but not in the small intestine. In vivo, PHA significantly increased CCK plasma levels from 0.75 to 6.67 (SEM 2.23) compared with 2.3 (0.35) pM in the control group. In addition, in vitro PHA dose dependently stimulated CCK release with a maximal effect at 100 ng/ml.Conclusion—In vivo and in vitro PHA is a potent stimulus for CCK release in the rat, thereby inducing pancreatic growth, whereas intestinal growth is stimulated by a CCK independent mechanism.

In Vivo CCK Release by Microdialysis

2006 ◽  
pp. 971-972
Keyword(s):  
Cck Release

Fine Structural Changes in the Microvasculature of the Mouse Pinna: Aging and Radiation Injury

1974 ◽  
Vol 32 ◽  
pp. 54-55
Author(s):  
S. Phyllis Steamer ◽  
Rosemarie L. Devine
Keyword(s):  
Structural Changes ◽  
Radiation Treatment ◽  
Arterial Stenosis ◽  
Ultrastructural Changes ◽  
Vascular Effects ◽  
Microvascular Changes ◽  
Surrounding Connective Tissue ◽  
Fission Neutrons ◽  
Total Body

The importance of radiation damage to the skin and its vasculature was recognized by the early radiologists. In more recent studies, vascular effects were shown to involve the endothelium as well as the surrounding connective tissue. Microvascular changes in the mouse pinna were studied in vivo and recorded photographically over a period of 12-18 months. Radiation treatment at 110 days of age was total body exposure to either 240 rad fission neutrons or 855 rad 60Co gamma rays. After in vivo observations in control and irradiated mice, animals were sacrificed for examination of changes in vascular fine structure. Vessels were selected from regions of specific interest that had been identified on photomicrographs. Prominent ultrastructural changes can be attributed to aging as well as to radiation treatment. Of principal concern were determinations of ultrastructural changes associated with venous dilatations, segmental arterial stenosis and tortuosities of both veins and arteries, effects that had been identified on the basis of light microscopic observations. Tortuosities and irregularly dilated vein segments were related to both aging and radiation changes but arterial stenosis was observed only in irradiated animals.

Induction and Differentiation of Dental Epithelium in Vivo and in Vitro

1982 ◽  
Vol 40 ◽  
pp. 142-145
Author(s):  
E. J. Kollar
Keyword(s):  
Connective Tissue ◽  
Oral Mucosa ◽  
Basal Lamina ◽  
Functional Derivatives ◽  
Specific Source ◽  
Dental Epithelium ◽  
Connective Tissue Stroma

The differentiation and maintenance of many specialized epithelial structures are dependent on the underlying connective tissue stroma and on an intact basal lamina. These requirements are especially stringent in the development and maintenance of the skin and oral mucosa. The keratinization patterns of thin or thick cornified layers as well as the appearance of specialized functional derivatives such as hair and teeth can be correlated with the specific source of stroma which supports these differentiated expressions.

Ultrastructural Correlations between Clonal Human Tumor Colonies and in Vivo Neoplasms

1982 ◽  
Vol 40 ◽  
pp. 210-211
Author(s):  
M.J. Murphy ◽  
R.R. Price ◽  
J.C. Sloman
Keyword(s):  
Cultured Cells ◽  
Human Tumor ◽  
Cell Type ◽  
Tumor Mass ◽  
Initial Cell ◽  
Cloning Assay ◽  
Human Tumor Cloning ◽  
The Relationship

The in vitro human tumor cloning assay originally described by Salmon and Hamburger has been applied recently to the investigation of differential anti-tumor drug sensitivities over a broad range of human neoplasms. A major problem in the acceptance of this technique has been the question of the relationship between the cultured cells and the original patient tumor, i.e., whether the colonies that develop derive from the neoplasm or from some other cell type within the initial cell population. A study of the ultrastructural morphology of the cultured cells vs. patient tumor has therefore been undertaken to resolve this question. Direct correlation was assured by division of a common tumor mass at surgical resection, one biopsy being fixed for TEM studies, the second being rapidly transported to the laboratory for culture.

Structural analysis of the photosynthetic membrane from Ectothiorhodospira halochloris

1983 ◽  
Vol 41 ◽  
pp. 740-741
Author(s):  
H. Engelhardt ◽  
R. Guckenberger ◽  
W. Baumeister
Keyword(s):  
Lattice Structure ◽  
Bacterial Species ◽  
Hexagonal Lattice ◽  
Reaction Centre ◽  
Photosynthetic Membrane ◽  
Rhodopseudomonas Viridis ◽  
Photosynthetic Membranes ◽  
Ectothiorhodospira Halochloris ◽  
Main Components

Bacterial photosynthetic membranes contain, apart from lipids and electron transport components, reaction centre (RC) and light harvesting (LH) polypeptides as the main components. The RC-LH complexes in Rhodopseudomonas viridis membranes are known since quite seme time to form a hexagonal lattice structure in vivo; hence this membrane attracted the particular attention of electron microscopists. Contrary to previous claims in the literature we found, however, that 2-D periodically organized photosynthetic membranes are not a unique feature of Rhodopseudomonas viridis. At least five bacterial species, all bacteriophyll b - containing, possess membranes with the RC-LH complexes regularly arrayed. All these membranes appear to have a similar lattice structure and fine-morphology. The lattice spacings of the Ectothiorhodospira haloohloris, Ectothiorhodospira abdelmalekii and Rhodopseudomonas viridis membranes are close to 13 nm, those of Thiocapsa pfennigii and Rhodopseudomonas sulfoviridis are slightly smaller (∼12.5 nm).

The Infection of Cells by Bullet-Shaped Viruses

1969 ◽  
Vol 27 ◽  
pp. 372-373
Author(s):  
Frederick A. Murphy ◽  
Alyne K. Harrison ◽  
Sylvia G. Whitfield
Keyword(s):  
Electron Microscopy ◽  
Physical Properties ◽  
Host Cell ◽  
Thin Section ◽  
Cultured Cells ◽  
Cell Infection ◽  
Thin Section Electron Microscopy ◽  
Section Electron ◽  
Section Electron Microscopy

The bullet-shaped viruses are currently classified together on the basis of similarities in virion morphology and physical properties. Biologically and ecologically the member viruses are extremely diverse. In searching for further bases for making comparisons of these agents, the nature of host cell infection, both in vivo and in cultured cells, has been explored by thin-section electron microscopy.

Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

1978 ◽  
Vol 36 (2) ◽  
pp. 650-651
Author(s):  
Raul I. Garcia ◽  
Evelyn A. Flynn ◽  
George Szabo
Keyword(s):  
Direct Injection ◽  
Skin Pigmentation ◽  
Freeze Fracture ◽  
Pigment Granule ◽  
Time Lapse ◽  
Ultrastructural Level ◽  
Lanthanum Tracer ◽  
A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

Effect of Some Metabolic Inhibitors on Vinblastine-Induced Ribosomal-Granular Material Complexes

1971 ◽  
Vol 29 ◽  
pp. 548-549
Author(s):  
Awtar Krishan ◽  
Dora Hsu
Keyword(s):  
Granular Material ◽  
Rna Synthesis ◽  
Culture Medium ◽  
Actinomycin D ◽  
Metabolic Inhibitors ◽  
Protein And Rna Synthesis ◽  
Apparent Reduction ◽  
Plant Alkaloids ◽  
In Cells

Cells exposed to antitumor plant alkaloids, vinblastine and vincristine sulfate have large proteinacious crystals and complexes of ribosomes, helical polyribosomes and electron-dense granular material (ribosomal complexes) in their cytoplasm, Binding of H3-colchicine by the in vivo crystals shows that they contain microtubular proteins. Association of ribosomal complexes with the crystals suggests that these structures may be interrelated.In the present study cultured human leukemic lymphoblasts (CCRF-CEM), were incubated with protein and RNA-synthesis inhibitors, p. fluorophenylalanine, puromycin, cycloheximide or actinomycin-D before the addition of crystal-inducing doses of vinblastine to the culture medium. None of these compounds could completely prevent the formation of the ribosomal complexes or the crystals. However, in cells pre-incubated with puromycin, cycloheximide, or actinomycin-D, a reduction in the number and size of the ribosomal complexes was seen. Large helical polyribosomes were absent in the ribosomal complexes of cells treated with puromycin, while in cells exposed to cycloheximide, there was an apparent reduction in the number of ribosomes associated with the ribosomal complexes (Fig. 2).

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