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ATROPINE INHIBITS THROMBOXANE A 2 GENERATION IN ISOLATED LUNGS OF THE GUINEA‐PIG
Author(s) -
BERTI F.,
FOLCO G.C.,
GIACHETTI A.,
MALANDRINO S.,
OMINI G.,
VIGANÒ T.
Publication year - 1980
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1980.tb14560.x
Subject(s) - histamine , carbachol , atropine , chemistry , thromboxane a2 , ovalbumin , endocrinology , guinea pig , medicine , thromboxane , acetylcholine , ipratropium bromide , prostaglandin , hexamethonium , thromboxane b2 , leukotriene , pharmacology , immunology , biochemistry , stimulation , platelet , bronchodilator , asthma , immune system
1 Histamine (0.5 to 5 μg) and slow reacting substance of anaphylaxis (SRS‐A, 0.05 to 0.3 u), injected in the isolated, perfused lungs of normal and ovalbumin‐sensitized guinea‐pigs, promote formation and release of thromboxane A 2 (TXA 2 ) and other arachidonate metabolites, the effect being more pronounced in sensitized lungs. 2 Carbachol injected (1 to 10 μg) or perfused (1 μg ml −1 min −1 ) through normal or sensitized lungs does not elicit formation of TXA 2 and prostaglandins. Furthermore the increased generation of arachidonate metabolites due to histamine is not altered by carbachol. 3 Atropine and ipratropium bromide (1 μg ml −1 min −1 ) reduce significantly the increased rate of production of TXA 2 caused by histamine and SRS‐A both in normal and sensitized lungs, whereas hexamethonium (10 to 25 μg ml −1 min −1 ) is ineffective. 4 The mechanism of action of atropine in inhibiting the increased generation of TXA 2 is clearly not related to its antimuscarinic or antihistaminic properties. The drug might act at the early events, involved in the activation of arachidonic acid metabolism. The results suggest new sites of action for atropine which, besides the control of the vagal bronchomotor tone, interferes directly with the primary mediators of anaphylaxis.