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Evidence for in vitro expression of B 1 receptor in the mouse trachea and urinary bladder
Author(s) -
Trevisani Marcello,
Schmidlin Fabien,
Tognetto Michele,
Nijkamp Frans P,
Gies JeanPierre,
Frossard Nelly,
Amadesi Silvia,
Folkerts Gert,
Geppetti Pierangelo
Publication year - 1999
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 - 10.1038/sj.bjp.0702410
Subject(s) - in vitro , urinary bladder , urinary system , receptor , biology , medicine , anatomy , biochemistry
Motor responses to des‐Arg 9 ‐bradykinin and bradykinin were studied in the isolated mouse trachea (precontracted with carbachol, 10 μ M ) and the urinary bladder of either Swiss, C57Bl/6J or bradykinin B 2 receptor knockout ( Bk2r −/− ) mice after 1–6 h in vitro . The expression of mRNA for the mouse B 1 receptor in tracheal and urinary bladder tissues was also studied by using Northern blot analysis. In isolated tracheae, des‐Arg 9 ‐bradykinin produced a relaxant response that increased over time: no response was observed after 1 h of incubation, whereas after 6 h the maximum response (1 μ M ) was 68–84% of the relaxation produced by isoproterenol (1 μ M ) in the three mouse strains. The relaxant response to bradykinin (1 μ M ) observed at 1 h (38–51% of isoproterenol) was increased (62–65% of isoproterenol) after 6 h in Swiss and C57Bl/6J mice, but was absent in Bk2r −/− mice. In the presence of cycloheximide, des‐Arg 9 ‐bradykinin did not cause any response at 6 h. Similar findings were obtained in the urinary bladder: at 1 h des‐Arg 9 ‐bradykinin (1 μ M ) did not cause any motor effect, whereas at 6 h it caused a contraction that was 28–59% of that produced by carbachol (1 μ M ) in the three mouse strains. Cycloheximide blocked the response to des‐Arg 9 ‐bradykinin. Bradykinin (1 μ M ) contracted urinary bladders at 1 h (34–35% of carbachol), as well as at 6 h (66–77% of carbachol) in Swiss and C57Bl/6J strains, but was without effect in Bk2r −/− mice. Northern blot hybridization with a specific cDNA probe against mouse B 1 receptor mRNA using total RNA extracted from tracheae and urinary bladders freshly removed from Swiss and Bk2r −/− mice revealed minimal expression. However, marked hybridization was detected 150 min after in vitro exposure in both tissues. Evidence is provided that in vitro exposure of mouse trachea and urinary bladder causes a time‐dependent induction of B 1 receptors that cause relaxation and contraction, respectively.British Journal of Pharmacology (1999) 126 , 1293–1300; doi: 10.1038/sj.bjp.0702410