scholarly journals Localized mast cell degranulation induced by concanavalin A-sepharose beads. Implications for the Ca2+ hypothesis of stimulus-secretion coupling.

1978 ◽  
Vol 79 (2) ◽  
pp. 394-400 ◽  
Author(s):  
D Lawson ◽  
C Fewtrell ◽  
M C Raff

Concanavalin A (Con A) covalently linked to Sepharose 4B beads induced localized degranulation of sensitized rat peritoneal mast cells in regions of contact between beads and cells. This degranulation was Ca2+ dependent and was not seen when sensitized mast cells bound to beads conjugated with a nonstimulating lectin, wheat germ agglutinin, or when unsensitized mast cells bound to Con A-Sepharose. The finding that sensitized mast cells which had adhered to Con A-Sepharose beads degranulated in regions of the cell away from the area of bead contact if exposed to soluble Con A excluded the possibility that the localized release was due to a redistribution of the IgE receptors or putative Ca2+ channels to the region of bead contact. The results suggest that, if an influx of Ca2+ is the mechanism for initiating mast cell degranulation, then the opening of Ca2+ channels in the plasma membrane of activated mast cells is a localized event and that Ca2+ acts locally within the cell to initiate exocytosis.

1999 ◽  
Vol 86 (1) ◽  
pp. 202-210 ◽  
Author(s):  
N. Noviski ◽  
J. P. Brewer ◽  
W. A. Skornik ◽  
S. J. Galli ◽  
J. M. Drazen ◽  
...  

Exposure to ambient ozone (O3) is associated with increased exacerbations of asthma. We sought to determine whether mast cell degranulation is induced by in vivo exposure to O3in mice and whether mast cells play an essential role in the development of pulmonary pathophysiological alterations induced by O3. For this we exposed mast cell-deficient WBB6F1- kitW/ kitW-v( kitW/ kitW-v) mice and the congenic normal WBB6F1(+/+) mice to air or to 1 or 3 parts/million O3for 4 h and studied them at different intervals from 4 to 72 h later. We found evidence of O3-induced cutaneous, as well as bronchial, mast cell degranulation. Polymorphonuclear cell influx into the pulmonary parenchyma was observed after exposure to 1 part/milllion O3only in mice that possessed mast cells. Airway hyperresponsiveness to intravenous methacholine measured in vivo under pentobarbital anesthesia was observed in both kitW/ kitW-vand +/+ mice after exposure to O3. Thus, although mast cells are activated in vivo by O3and participate in O3-induced polymorphonuclear cell infiltration into the pulmonary parenchyma, they do not participate detectably in the development of O3-induced airway hyperresponsiveness in mice.


1989 ◽  
Vol 88 (1-2) ◽  
pp. 200-202
Author(s):  
M. Swieter ◽  
B.M.C. Chan ◽  
T.D.G. Lee ◽  
C.J. Rimmer ◽  
A. Froese ◽  
...  

2002 ◽  
Vol 282 (6) ◽  
pp. H2152-H2158 ◽  
Author(s):  
Amanda L. Chancey ◽  
Gregory L. Brower ◽  
Joseph S. Janicki

Mast cells contain proteases capable of activating matrix metalloproteinases (MMPs). However, given the relatively low density of mast cells in the myocardium (i.e., 1.5–5.3 cells/mm2), it is unknown whether these enzymes are present in sufficient quantities in the normal heart to mediate MMP activation. Accordingly, this study sought to determine whether chemically induced degranulation of cardiac mast cells (with compound 48/80) would have an effect in isolated, blood-perfused, functioning rat hearts. Mast cell degranulation produced a 15% increase in histamine levels present in the coronary efflux, a significant increase in myocardial water (i.e., edema) relative to normal values (80.1 ± 3.4% vs. 77.4 ± 1.08%, P≤ 0.03), a substantial activation of MMP-2 (126% increase relative to controls, P ≤ 0.02), and a marked decrease in myocardial collagen volume fraction (0.46 ± 0.10% vs. 0.97 ± 0.33%, P ≤ 0.001). Furthermore, although an increase in ventricular stiffness was expected due to the extent of edema resulting from mast cell degranulation, modest ventricular dilatation was observed. These findings clearly demonstrate that the number of mast cells present in normal hearts is sufficient to mediate activation of MMPs and produce extracellular matrix degradation, thereby potentially causing subsequent ventricular dilatation.


2008 ◽  
Vol 295 (5) ◽  
pp. H1825-H1833 ◽  
Author(s):  
Tyler H. Rork ◽  
Kori L. Wallace ◽  
Dylan P. Kennedy ◽  
Melissa A. Marshall ◽  
Amy R. Lankford ◽  
...  

Mast cells are found in the heart and contribute to reperfusion injury following myocardial ischemia. Since the activation of A2Aadenosine receptors (A2AARs) inhibits reperfusion injury, we hypothesized that ATL146e (a selective A2AAR agonist) might protect hearts in part by reducing cardiac mast cell degranulation. Hearts were isolated from five groups of congenic mice: A2AAR+/+mice, A2AAR−/−mice, mast cell-deficient (KitW-sh/W-sh) mice, and chimeric mice prepared by transplanting bone marrow from A2AAR−/−or A2AAR+/+mice to radiation-ablated A2AAR+/+mice. Six weeks after bone marrow transplantation, cardiac mast cells were repopulated with >90% donor cells. In isolated, perfused hearts subjected to ischemia-reperfusion injury, ATL146e or CGS-21680 (100 nmol/l) decreased infarct size (IS; percent area at risk) from 38 ± 2% to 24 ± 2% and 22 ± 2% in ATL146e- and CGS-21680-treated hearts, respectively ( P < 0.05) and significantly reduced mast cell degranulation, measured as tryptase release into reperfusion buffer. These changes were absent in A2AAR−/−hearts and in hearts from chimeric mice with A2AAR−/−bone marrow. Vehicle-treated KitW-sh/W-shmice had lower IS (11 ± 3%) than WT mice, and ATL146e had no significant protective effect (16 ± 3%). These data suggest that in ex vivo, buffer-perfused hearts, mast cell degranulation contributes to ischemia-reperfusion injury. In addition, our data suggest that A2AAR activation is cardioprotective in the isolated heart, at least in part by attenuating resident mast cell degranulation.


1997 ◽  
Vol 272 (5) ◽  
pp. H2154-H2163 ◽  
Author(s):  
M. W. Keller

Striated muscle becomes stunned during reperfusion after sublethal ischemia. Resistance vessel tone and reactivity are altered in stunned muscle tissues. The hypothesis that adenosine-regulated mast cell degranulation occurs during reperfusion and leads to constriction of resistance arterioles was tested. The hamster cremaster muscle was subjected to 1 h of ischemia followed by reperfusion. Resistance arterioles constricted during reperfusion (74% of maximal diameter at baseline vs. 42% of maximal diameter after 30 min of reperfusion; P < 0.01). Mast cells degranulated in reperfusion concomitant with arteriolar constriction. Stimulation of mast cell degranulation in control animals with compound 48/80 or cold superfusate (21 degrees C) caused vasoconstriction that mimicked that seen in reperfusion. The mast cell stabilizer cromolyn blocked degranulation and constriction. If mast cell granules were depleted by applying compound 48/80 before inducing ischemia, then arterioles failed to constrict during reperfusion. Adenosine A3-antagonist BW-A1433 abolished constriction. These findings suggest that arterioles constrict in reperfusion due to adenosine-regulated mast cell degranulation. Vasodilation in response to sodium nitroprusside and acetylcholine was normal in stunned, constricted arterioles. However, the dose-response curves to adenosine were shifted to the left in arterioles constricted by either stunning, compound 48/80, exposure to cold superfusate, or cromolyn compared with control vessels. Depletion of granular components via stunning, compound 48/80, cold superfusate, or inhibition of secretion with cromolyn results in unopposed A1- or A2-mediated vasodilation in response to adenosine, whereas the dilatory effects of adenosine are blunted by simultaneous release of vasoconstrictors from mast cells in control animals. In summary, it was found that mast cell degranulation occurs during reperfusion and leads to constriction of resistance arterioles and altered vascular reactivity to adenosine. Adenosine is released in ischemia and stimulates mast cell degranulation via the A3 receptor located on mast cells during reperfusion.


1979 ◽  
Vol 178 (3) ◽  
pp. 681-687 ◽  
Author(s):  
Shamshad Cockcroft ◽  
Bastien D. Gomperts

Histamine secretion and phosphatidylinositol turnover were compared in antigen-sensitized rat peritoneal mast cells stimulated with a number of different ligands. A small and variable increase in the incorporation of [32P]Pi and of [3H]inositol into phosphatidylinositol was observed when the cells were treated with immunoglobulin E-directed ligands (antigens and concanavalin A), and this was accompanied by a low amount of secretion (<10% of total cell histamine). In the presence of added phosphatidylserine, the addition of immunoglobulin E-directed ligands invariably led to an enhanced rate (approx. 4-fold) of labelling of phosphatidylinositol and, in the presence of Ca2+, this was accompanied by the secretion of histamine. The labelling of phosphatidylinositol and histamine secretion were also stimulated by chymotrypsin and compound 48/80. Whereas the phosphatidylinositol response did not require the presence of extracellular Ca2+, the secretion of histamine was either enhanced or dependent on extracellular Ca2+ (depending on the ligand used). The dependence on ligand concentration for the phosphatidylinositol response and histamine secretion were similar. The increased isotopic incorporation into phosphatidylinositol continued for about 1h although histamine secretion (elicited with concanavalin A) stopped within 2min. These results support the proposition that metabolic events involving phosphatidylinositol play a necessary intermediate role in the regulation of Ca2+ channels by ligand-activated receptors.


1999 ◽  
Vol 276 (6) ◽  
pp. S19
Author(s):  
J Corado ◽  
A Eblen-Zajjur

A simple experimental model of cell degranulation was implemented that exposed mast cells obtained from Sprague-Dawley rats to saponin. The model is flexible, asy, and low cost, is not very time-consuming to run, and needs a minimum of laboratory resources. It has been used for the last three years in our undergraduate medical physiology courses and has replaced the classic utilization of slides and drawings.


2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Xuezhi Wang ◽  
Meng Huang ◽  
Hongwei Yang ◽  
Di Zhang ◽  
Wei Yao ◽  
...  

Acupuncture is a medical modality based on the theory of traditional Chinese medicine, and its effect is relatively dependent on acupoint specificity. However, there is little knowledge on acupoint specificity versus acupuncture outcomes because of the deficiency of rigorous investigation on this topic, which has impeded the growing legitimacy of acupuncture in the mainstream of medicine as an evidence-based therapy. Therefore, it is of utmost importance to clarify this critical issue. The present study aims to verify the phenomenon of acupoint specificity in acupuncture-induced cardiovascular regulation and explore the biological mechanism by measuring mast cells’ degranulation and adenosine release. This study was conducted to explore the specificity of acupoints in an acute bradycardia rabbit model. After electroacupuncture (EA) stimulation at PC6, PC control (con) 1, PC con 2, LU7, LI11, and nonacupoint, only the PC6 group showed a significant improvement in relative heart rate as compared to that of the model group. There was no significant difference between the relative heart rate of other EA groups and that of the model group. Historical results also showed that the ratio of degranulated mast cells in PC6 was significantly higher than other acupoints and control points. From the results of high-performance liquid chromatography (HPLC), a transient elevation of adenosine concentration during EA was only observed on acupoints and control points ( P < 0.05 ) along the pericardium meridian. The EA-induced adjustment on acute bradycardia exhibits a relative specificity of acupoints, which may be related to mast cell degranulation and adenosine release in local acupoint areas. Increased degranulation of mast cells and augmentation of adenosine release during EA may be the mechanisms for PC6 having significantly better acupuncture effects than other acupoints and nonacupoints.


1976 ◽  
Vol 85 (2_suppl) ◽  
pp. 117-123 ◽  
Author(s):  
David J. Lim ◽  
Yea S. Liu ◽  
James Schram ◽  
Herbert G. Birck

A total of 61 middle ear effusions and matched sera obtained from patients suffering from chronic otitis media with effusions (OME) was examined for IgE and other immunoglobulins to see if a reaginic antibody is involved in OME. The IgE levels were determined by the Phadebas IgE radioimmunoassay test. Excluding one patient who had extremely high IgE as a result of parasitosis, there were only three cases which showed marginally increased serum IgE levels. Elevated IgE levels in sera and/or in effusions were unrelated to a history of allergy. The mucoid effusions had significantly higher effusion levels than the levels in corresponding sera (p <.0005). Fourteen percent of the cases examined showed effusion IgE levels five times or more higher than serum levels. Biopsy specimens of these patients showed numerous degranulating mast cells. Only two specimens showed eosinophilic infiltration. It is suggested that the IgE is produced locally by the mucosa in mucoid-type effusions and may have been involved in mast cell degranulation. However, this study cannot confirm the allergic nature of the OME.


Sign in / Sign up

Export Citation Format

Share Document