Premium
Bronchodilatation of guinea‐pig perfused bronchioles induced by the H 3 ‐receptor for histamine: role of epithelium
Author(s) -
Burgaud J.L.,
Oudart N.
Publication year - 1993
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.1476-5381.1993.tb13714.x
Subject(s) - bronchodilatation , thioperamide , histamine , chemistry , endocrinology , guinea pig , medicine , agonist , respiratory epithelium , receptor , pharmacology , biology , histamine h3 receptor , biochemistry , bronchodilator , lung , asthma
1 The influence of epithelium on the effects of H 3 ‐histamine receptor agonist ( R )α‐methylhistamine [( R )α‐MeHist] on airways was investigated on the guinea‐pig perfused bronchioles. 2 In preparations under resting tone, removal of the bronchiolar epithelium or treatment with the cyclo‐oxygenase inhibitor indomethacin (10 −5 m ) increased the constriction induced by histamine and acetylcholine in a concentration‐dependent manner without an alteration of the K + ‐induced contraction. 3 In this preparation ( R )α‐MeHist induced a concentration‐dependent bronchodilatation which was antagonized in a competitive manner by thioperamide (an H 3 ‐antagonist) with a pA 2 value of 8.6. 4 This bronchodilatation was reversed to a low concentration‐dependent constriction after either removal of the epithelium or treatment with indomethacin (10 −5 m ) but was unaffected by both 10 −5 m tranylcypromine (an inhibitor of PGI 2 synthesis) and 5 × 10 −5 m N G ‐nitro‐ l ‐arginine methyl ester (an inhibitor of NO synthesis). 5 It is suggested that, in guinea‐pig perfused bronchioles ( R )α‐MeHist induces an epithelium‐dependent relaxation via the release of metabolite(s) of arachidonic acid.