Biomedical subjects

K E Barrett

Publications and source records attributed to K E Barrett.

118 records · Page 7Linked to original sources

PubMed1983

Histamine secretion from mast cells treated with chlortetracycline (aureomycin): a novel calcium ionophore.

The novel calcium ionophore chlortetracycline (CTC) induced histamine secretion (less than or equal to 90%) from isolated rat peritoneal mast cells in a pH and dose-dependent fashion. The process was dependent on exogenous calcium ions and was inhibited by extremes of temperature and metabolic blockers. The release was rapid, being essentially complete within 1 min, but the half-life of the process varied inversely with the concentration of the ionophore. In contrast to receptor-mediated ligands, but in keeping with other ionophores, the activated state induced by CTC did not decay with time. The secretion was effectively inhibited, according to the concentration of the ionophore, by disodium cromoglycate and other anti-allergic or cyclic AMP-active drugs. These results confirm our previous contention that these agents do not act on receptor-mediated calcium-channels. CTC induced a significant (less than or equal to 50%) release of histamine from enzymically dispersed rat mesenteric mast cells but was essentially inactive against isolated mast cells from the mesentery or lung of the guinea-pig. These results extend our former observations on the functional heterogeneity of mast cells and show that, in common with other secretagogues, ionophores may exhibit selectivity in their mode of action.

Animals↗

PubMed1983

Mast cells isolated from guinea-pig lung: characterization and studies on histamine secretion.

A method has been developed for the dispersion of guinea-pig lung into its component cells using the proteolytic enzyme collagenase. The procedure typically yielded 5 X 10(6) mast cells per g of tissue with a recovery of histamine of ca. 20%. The mast cells comprised 2% of the total nucleated cells, had a histamine content of 1-2 pg per cell and exhibited a low spontaneous release of the amine (ca. 6%). In contrast to the rat peritoneal mast cell, guinea-pig lung mast cells were refractory to the action of compound 48/80, peptide 401 (MCD-peptide), dextran and Concanavalin A. However, the cells released histamine on antigenic challenge following active sensitization and dose-dependent histamine secretion was also produced by the ionophores A23187, ionomycin and Br-X537A. These results further emphasize the functional heterogeneity of mast cells obtained from different species and tissues.

Animals↗

PubMed1983

A comparison of histamine secretion from isolated peritoneal mast cells of the mouse and rat.

The effect of different histamine liberators on isolated peritoneal mast cells of the mouse and rat has been examined. Both cell types responded to the lectin, concanavalin A, and the release was in each case potentiated by phosphatidylserine. The rat cells released histamine on treatment with dextran but the mouse cells were essentially refractory to the polysaccharide. The mouse cells were significantly more responsive to the actions of the ionophore A23187 and adenosine 5'-triphosphate but much less reactive towards the polycations, compound 48/80 and peptide 401 (the MCD-peptide from bee venom). The reactivity of the mouse cells towards the latter two agents was enhanced in the absence of extracellular calcium. These results further emphasize the functional heterogeneity of mast cells from different sources.

Adenosine Triphosphate↗

PubMed1982

A comparative study of histamine secretion from rat peritoneal and pleural mast cells.

The effects of various histamine liberators and inhibitors on isolated rat peritoneal and pleural mast cells have been compared. The pleural cells showed an increased reactivity to challenge with antigen following passive, but not active, sensitization and were more responsive to challenge with anti-IgE. Phosphatidyl serine enhanced the secretion from both cell types. Peritoneal and pleural cells exhibited virtually identical responses after treatment with chemical secretagogues in the presence of exogenous calcium, but the peritoneal cells were significantly more reactive to stimulation with basic inducers in the absence of the cation. Anaphylactic histamine secretion was comparably inhibited by a number of anti-allergic drugs but the peritoneal cells were rather more sensitive to inhibition by dibutyryl cyclic AMP. These results are discussed in terms of the general functional heterogeneity of mast cells from different sources.

Anaphylaxis↗

PubMed1972