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See detailSelective implication of thromboxane A2 and PAF-acether in two guinea pig anaphylactic models
Bertrand, C.; Tschirhart, Eric UL; Landry, Y.

in Agents and Actions. Supplements (1991), 31

In an IgE and an IgG model of anaphylaxis in the guinea pig, we investigated the role of prostanoids and PAF-acether in the tracheal response in vitro to immunochallenge. Indomethacin (10(-6) M ... [more ▼]

In an IgE and an IgG model of anaphylaxis in the guinea pig, we investigated the role of prostanoids and PAF-acether in the tracheal response in vitro to immunochallenge. Indomethacin (10(-6) M) potentiated the antigen-induced contraction in both models suggesting the synthesis of relaxant prostaglandins during the anaphylactic phenomenon. UK-38,485 (10(-5) M), a thromboxane (TxA2) synthetase inhibitor, did not modify the tracheal response in the IgE model. In the IgG model, this drug reduced the response of the tracheal strips to antigen. Ro 19-3704 (10(-6) M) and BN 52021 (10(-5) M), two potent PAF antagonists, reduced antigen-induced contraction of the tracheal strips in the IgE model. These two drugs did not modify the contractile response in the IgG model. These results indicate that PAF-acether and TxA2 play a role in the IgE and IgG model of anaphylaxis, respectively. [less ▲]

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See detailBinding characteristics of [125I]endothelin-1 in guinea-pig trachea and its displacement by endothelin-1, endothelin-3 and endothelin (16-21)
Tschirhart, Eric UL; Pelton, J. T.; Jones, C. R.

in Agents and Actions. Supplements (1991), 31

The presence of binding sites for endothelin-1 (ET-1) and endothelin-3 (ET-3) in airway epithelium, submucosa and smooth muscle of guinea-pig trachea was investigated using in vitro autoradiography. We ... [more ▼]

The presence of binding sites for endothelin-1 (ET-1) and endothelin-3 (ET-3) in airway epithelium, submucosa and smooth muscle of guinea-pig trachea was investigated using in vitro autoradiography. We also examined the ability of the C-terminal hexapeptide of endothelin, ET(16-21) to inhibit specific [125I]ET-1, binding. ET-1 appeared to bind to a single class of binding sites (nH not different from unity). In contrast, nH values for ET-3 displacement of [125I]ET-1 specific binding were different from unity, suggesting that these peptides bound to more than one site. ET (16-21) did not affect [125I]ET-1 binding. The present results suggest that the binding sites identified in guinea pig airway smooth muscle may be related to receptors mediating contractile responses to the endothelins. [less ▲]

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